diff --git a/src/libraries/System.Linq.Parallel/src/System.Linq.Parallel.csproj b/src/libraries/System.Linq.Parallel/src/System.Linq.Parallel.csproj
index dc8a4cd971b57e..af337bc39dd611 100644
--- a/src/libraries/System.Linq.Parallel/src/System.Linq.Parallel.csproj
+++ b/src/libraries/System.Linq.Parallel/src/System.Linq.Parallel.csproj
@@ -5,7 +5,12 @@
     <AllowUnsafeBlocks>true</AllowUnsafeBlocks>
     <UseCompilerGeneratedDocXmlFile>false</UseCompilerGeneratedDocXmlFile>
   </PropertyGroup>
-
+  <PropertyGroup>
+    <TargetPlatformIdentifier>$([MSBuild]::GetTargetPlatformIdentifier('$(TargetFramework)'))</TargetPlatformIdentifier>
+    <FeatureWasmThreads Condition="'$(TargetPlatformIdentifier)' == 'browser' and '$(MonoWasmBuildVariant)' == 'multithread'">true</FeatureWasmThreads>
+    <DefineConstants Condition="'$(FeatureWasmThreads)' == 'true'" >$(DefineConstants);FEATURE_WASM_THREADS</DefineConstants>
+  </PropertyGroup>
+  <!-- Compiled Source Files -->
   <ItemGroup>
     <Compile Include="System\Linq\Parallel\Channels\AsynchronousChannel.cs" />
     <Compile Include="System\Linq\Parallel\Channels\SynchronousChannel.cs" />
diff --git a/src/libraries/System.Linq.Parallel/src/System/Linq/ParallelEnumerable.cs b/src/libraries/System.Linq.Parallel/src/System/Linq/ParallelEnumerable.cs
index 1da235729da749..0552ded75cb5f2 100644
--- a/src/libraries/System.Linq.Parallel/src/System/Linq/ParallelEnumerable.cs
+++ b/src/libraries/System.Linq.Parallel/src/System/Linq/ParallelEnumerable.cs
@@ -64,8 +64,12 @@ public static class ParallelEnumerable
 
         // When running in single partition mode, PLINQ operations will occur on a single partition and will not
         // be executed in parallel, but will retain PLINQ semantics (exceptions wrapped as aggregates, etc).
+#if !FEATURE_WASM_THREADS
         [System.Runtime.Versioning.SupportedOSPlatformGuard("browser")]
         internal static bool SinglePartitionMode => OperatingSystem.IsBrowser();
+#else
+        internal static bool SinglePartitionMode => false;
+#endif
 
         //-----------------------------------------------------------------------------------
         // Converts any IEnumerable<TSource> into something that can be the target of parallel
diff --git a/src/libraries/System.Threading.Tasks.Parallel/src/System.Threading.Tasks.Parallel.csproj b/src/libraries/System.Threading.Tasks.Parallel/src/System.Threading.Tasks.Parallel.csproj
index 7272b6a3d1b009..8d96b68a876420 100644
--- a/src/libraries/System.Threading.Tasks.Parallel/src/System.Threading.Tasks.Parallel.csproj
+++ b/src/libraries/System.Threading.Tasks.Parallel/src/System.Threading.Tasks.Parallel.csproj
@@ -5,7 +5,11 @@
     <AllowUnsafeBlocks>true</AllowUnsafeBlocks>
     <UseCompilerGeneratedDocXmlFile>false</UseCompilerGeneratedDocXmlFile>
   </PropertyGroup>
-
+  <PropertyGroup>
+    <TargetPlatformIdentifier>$([MSBuild]::GetTargetPlatformIdentifier('$(TargetFramework)'))</TargetPlatformIdentifier>
+    <FeatureWasmThreads Condition="'$(TargetPlatformIdentifier)' == 'browser' and '$(MonoWasmBuildVariant)' == 'multithread'">true</FeatureWasmThreads>
+    <DefineConstants Condition="'$(FeatureWasmThreads)' == 'true'" >$(DefineConstants);FEATURE_WASM_THREADS</DefineConstants>
+  </PropertyGroup>
   <ItemGroup>
     <Compile Include="System\Threading\Tasks\Parallel.cs" />
     <Compile Include="System\Threading\Tasks\Parallel.ForEachAsync.cs" />
diff --git a/src/libraries/System.Threading.Tasks.Parallel/src/System/Threading/Tasks/Parallel.cs b/src/libraries/System.Threading.Tasks.Parallel/src/System/Threading/Tasks/Parallel.cs
index 1ada79b833a11a..c08d76b8927c25 100644
--- a/src/libraries/System.Threading.Tasks.Parallel/src/System/Threading/Tasks/Parallel.cs
+++ b/src/libraries/System.Threading.Tasks.Parallel/src/System/Threading/Tasks/Parallel.cs
@@ -238,8 +238,12 @@ public static void Invoke(ParallelOptions parallelOptions, params Action[] actio
             {
                 // If we've gotten this far, it's time to process the actions.
 
+#if !FEATURE_WASM_THREADS
                 // Web browsers need special treatment that is implemented in TaskReplicator
                 if (OperatingSystem.IsBrowser() ||
+#else
+                if (
+#endif
                     // This is more efficient for a large number of actions, or for enforcing MaxDegreeOfParallelism:
                     (actionsCopy.Length > SMALL_ACTIONCOUNT_LIMIT) ||
                     (parallelOptions.MaxDegreeOfParallelism != -1 && parallelOptions.MaxDegreeOfParallelism < actionsCopy.Length)
diff --git a/src/libraries/System.Threading.Tasks.Parallel/src/System/Threading/Tasks/TaskReplicator.cs b/src/libraries/System.Threading.Tasks.Parallel/src/System/Threading/Tasks/TaskReplicator.cs
index 28287184542b39..eb09ba672f4239 100644
--- a/src/libraries/System.Threading.Tasks.Parallel/src/System/Threading/Tasks/TaskReplicator.cs
+++ b/src/libraries/System.Threading.Tasks.Parallel/src/System/Threading/Tasks/TaskReplicator.cs
@@ -131,6 +131,7 @@ public static void Run<TState>(ReplicatableUserAction<TState> action, ParallelOp
         {
             // Browser hosts do not support synchronous Wait so we want to run the
             //  replicated task directly instead of going through Task infrastructure
+#if !FEATURE_WASM_THREADS
             if (OperatingSystem.IsBrowser())
             {
                 // Since we are running on a single thread, we don't want the action to time out
@@ -142,6 +143,7 @@ public static void Run<TState>(ReplicatableUserAction<TState> action, ParallelOp
                     throw new Exception("Replicated tasks cannot yield in this single-threaded browser environment");
             }
             else
+#endif
             {
                 int maxConcurrencyLevel = (options.EffectiveMaxConcurrencyLevel > 0) ? options.EffectiveMaxConcurrencyLevel : int.MaxValue;
 
diff --git a/src/libraries/System.Threading.Tasks.Parallel/tests/ParallelForEachAsyncTests.cs b/src/libraries/System.Threading.Tasks.Parallel/tests/ParallelForEachAsyncTests.cs
index fbcbdc87f1931c..77c16ddd72c928 100644
--- a/src/libraries/System.Threading.Tasks.Parallel/tests/ParallelForEachAsyncTests.cs
+++ b/src/libraries/System.Threading.Tasks.Parallel/tests/ParallelForEachAsyncTests.cs
@@ -293,7 +293,6 @@ static IEnumerable<int> IterateUntilSet(StrongBox<bool> box)
         }
 
         [ConditionalFact(typeof(PlatformDetection), nameof(PlatformDetection.IsThreadingSupported))]
-        [ActiveIssue("https://github.com/dotnet/runtime/issues/91538", typeof(PlatformDetection), nameof(PlatformDetection.IsWasmThreadingSupported))]
         public async Task Dop_NegativeTaskSchedulerLimitTreatedAsDefault_Async()
         {
             static async IAsyncEnumerable<int> IterateUntilSet(StrongBox<bool> box)
@@ -328,7 +327,6 @@ static async IAsyncEnumerable<int> IterateUntilSet(StrongBox<bool> box)
         }
 
         [ConditionalFact(typeof(PlatformDetection), nameof(PlatformDetection.IsThreadingSupported))]
-        [ActiveIssue("https://github.com/dotnet/runtime/issues/91538", typeof(PlatformDetection), nameof(PlatformDetection.IsWasmThreadingSupported))]
         public async Task RunsAsynchronously_For()
         {
             var cts = new CancellationTokenSource();
@@ -342,7 +340,6 @@ public async Task RunsAsynchronously_For()
         }
 
         [ConditionalFact(typeof(PlatformDetection), nameof(PlatformDetection.IsThreadingSupported))]
-        [ActiveIssue("https://github.com/dotnet/runtime/issues/91538", typeof(PlatformDetection), nameof(PlatformDetection.IsWasmThreadingSupported))]
         public async Task RunsAsynchronously_EvenForEntirelySynchronousWork_Sync()
         {
             static IEnumerable<int> Iterate()
@@ -361,7 +358,6 @@ static IEnumerable<int> Iterate()
         }
 
         [ConditionalFact(typeof(PlatformDetection), nameof(PlatformDetection.IsThreadingSupported))]
-        [ActiveIssue("https://github.com/dotnet/runtime/issues/91538", typeof(PlatformDetection), nameof(PlatformDetection.IsWasmThreadingSupported))]
         public async Task RunsAsynchronously_EvenForEntirelySynchronousWork_Async()
         {
 #pragma warning disable CS1998 // Async method lacks 'await' operators and will run synchronously
@@ -382,7 +378,6 @@ static async IAsyncEnumerable<int> IterateAsync()
         }
 
         [ConditionalTheory(typeof(PlatformDetection), nameof(PlatformDetection.IsThreadingSupported))]
-        [ActiveIssue("https://github.com/dotnet/runtime/issues/91538", typeof(PlatformDetection), nameof(PlatformDetection.IsWasmThreadingSupported))]
         [InlineData(-1)]
         [InlineData(1)]
         [InlineData(2)]
@@ -422,7 +417,6 @@ static async IAsyncEnumerable<int> IterateUntilSetAsync(StrongBox<bool> box)
         }
 
         [ConditionalFact(typeof(PlatformDetection), nameof(PlatformDetection.IsThreadingSupported))]
-        [ActiveIssue("https://github.com/dotnet/runtime/issues/91538", typeof(PlatformDetection), nameof(PlatformDetection.IsWasmThreadingSupported))]
         public void EmptyRange_For()
         {
             int counter = 0;
@@ -437,7 +431,6 @@ public void EmptyRange_For()
         }
 
         [ConditionalFact(typeof(PlatformDetection), nameof(PlatformDetection.IsThreadingSupported))]
-        [ActiveIssue("https://github.com/dotnet/runtime/issues/91538", typeof(PlatformDetection), nameof(PlatformDetection.IsWasmThreadingSupported))]
         public async Task EmptySource_Sync()
         {
             int counter = 0;
@@ -451,7 +444,6 @@ await Parallel.ForEachAsync(Enumerable.Range(0, 0), (item, cancellationToken) =>
         }
 
         [ConditionalFact(typeof(PlatformDetection), nameof(PlatformDetection.IsThreadingSupported))]
-        [ActiveIssue("https://github.com/dotnet/runtime/issues/91538", typeof(PlatformDetection), nameof(PlatformDetection.IsWasmThreadingSupported))]
         public async Task EmptySource_Async()
         {
             int counter = 0;
@@ -465,7 +457,6 @@ await Parallel.ForEachAsync(EnumerableRangeAsync(0, 0), (item, cancellationToken
         }
 
         [ConditionalTheory(typeof(PlatformDetection), nameof(PlatformDetection.IsThreadingSupported))]
-        [ActiveIssue("https://github.com/dotnet/runtime/issues/91538", typeof(PlatformDetection), nameof(PlatformDetection.IsWasmThreadingSupported))]
         [InlineData(false)]
         [InlineData(true)]
         public async Task AllItemsEnumeratedOnce_For(bool yield)
@@ -511,7 +502,6 @@ await Parallel.ForAsync(T.CreateTruncating(Start), T.CreateTruncating(Start + Co
         }
 
         [ConditionalTheory(typeof(PlatformDetection), nameof(PlatformDetection.IsThreadingSupported))]
-        [ActiveIssue("https://github.com/dotnet/runtime/issues/91538", typeof(PlatformDetection), nameof(PlatformDetection.IsWasmThreadingSupported))]
         [InlineData(false)]
         [InlineData(true)]
         public async Task AllItemsEnumeratedOnce_Sync(bool yield)
@@ -542,7 +532,6 @@ await Parallel.ForEachAsync(Enumerable.Range(Start, Count), async (item, cancell
         }
 
         [ConditionalTheory(typeof(PlatformDetection), nameof(PlatformDetection.IsThreadingSupported))]
-        [ActiveIssue("https://github.com/dotnet/runtime/issues/91538", typeof(PlatformDetection), nameof(PlatformDetection.IsWasmThreadingSupported))]
         [InlineData(false)]
         [InlineData(true)]
         public async Task AllItemsEnumeratedOnce_Async(bool yield)
@@ -573,7 +562,6 @@ await Parallel.ForEachAsync(EnumerableRangeAsync(Start, Count, yield), async (it
         }
 
         [ConditionalTheory(typeof(PlatformDetection), nameof(PlatformDetection.IsThreadingSupported))]
-        [ActiveIssue("https://github.com/dotnet/runtime/issues/91538", typeof(PlatformDetection), nameof(PlatformDetection.IsWasmThreadingSupported))]
         [InlineData(false)]
         [InlineData(true)]
         public async Task TaskScheduler_AllCodeExecutedOnCorrectScheduler_For(bool defaultScheduler)
@@ -602,7 +590,6 @@ public async Task TaskScheduler_AllCodeExecutedOnCorrectScheduler_For(bool defau
         }
 
         [ConditionalTheory(typeof(PlatformDetection), nameof(PlatformDetection.IsThreadingSupported))]
-        [ActiveIssue("https://github.com/dotnet/runtime/issues/91538", typeof(PlatformDetection), nameof(PlatformDetection.IsWasmThreadingSupported))]
         [InlineData(false)]
         [InlineData(true)]
         public async Task TaskScheduler_AllCodeExecutedOnCorrectScheduler_Sync(bool defaultScheduler)
@@ -641,7 +628,6 @@ IEnumerable<int> Iterate()
         }
 
         [ConditionalTheory(typeof(PlatformDetection), nameof(PlatformDetection.IsThreadingSupported))]
-        [ActiveIssue("https://github.com/dotnet/runtime/issues/91538", typeof(PlatformDetection), nameof(PlatformDetection.IsWasmThreadingSupported))]
         [InlineData(false)]
         [InlineData(true)]
         public async Task TaskScheduler_AllCodeExecutedOnCorrectScheduler_Async(bool defaultScheduler)
@@ -681,7 +667,6 @@ async IAsyncEnumerable<int> Iterate()
         }
 
         [ConditionalFact(typeof(PlatformDetection), nameof(PlatformDetection.IsThreadingSupported))]
-        [ActiveIssue("https://github.com/dotnet/runtime/issues/91538", typeof(PlatformDetection), nameof(PlatformDetection.IsWasmThreadingSupported))]
         public async Task Cancellation_CancelsIterationAndReturnsCanceledTask_For()
         {
             using var cts = new CancellationTokenSource(10);
@@ -714,7 +699,6 @@ static async IAsyncEnumerable<int> Infinite()
         }
 
         [ConditionalFact(typeof(PlatformDetection), nameof(PlatformDetection.IsThreadingSupported))]
-        [ActiveIssue("https://github.com/dotnet/runtime/issues/91538", typeof(PlatformDetection), nameof(PlatformDetection.IsWasmThreadingSupported))]
         public async Task Cancellation_CancelsIterationAndReturnsCanceledTask_Async()
         {
             static async IAsyncEnumerable<int> InfiniteAsync()
@@ -736,7 +720,6 @@ static async IAsyncEnumerable<int> InfiniteAsync()
         }
 
         [ConditionalFact(typeof(PlatformDetection), nameof(PlatformDetection.IsThreadingSupported))]
-        [ActiveIssue("https://github.com/dotnet/runtime/issues/91538", typeof(PlatformDetection), nameof(PlatformDetection.IsWasmThreadingSupported))]
         public async Task Cancellation_CorrectTokenPassedToAsyncEnumerator()
         {
             static async IAsyncEnumerable<CancellationToken> YieldTokenAsync([EnumeratorCancellation] CancellationToken cancellationToken)
@@ -753,7 +736,6 @@ await Parallel.ForEachAsync(YieldTokenAsync(default), (item, cancellationToken)
         }
 
         [ConditionalFact(typeof(PlatformDetection), nameof(PlatformDetection.IsThreadingSupported))]
-        [ActiveIssue("https://github.com/dotnet/runtime/issues/91538", typeof(PlatformDetection), nameof(PlatformDetection.IsWasmThreadingSupported))]
         public async Task Cancellation_SameTokenPassedToEveryInvocation_For()
         {
             var cq = new ConcurrentQueue<CancellationToken>();
@@ -769,7 +751,6 @@ await Parallel.ForAsync(1, 101, async (item, cancellationToken) =>
         }
 
         [ConditionalFact(typeof(PlatformDetection), nameof(PlatformDetection.IsThreadingSupported))]
-        [ActiveIssue("https://github.com/dotnet/runtime/issues/91538", typeof(PlatformDetection), nameof(PlatformDetection.IsWasmThreadingSupported))]
         public async Task Cancellation_SameTokenPassedToEveryInvocation_Sync()
         {
             var cq = new ConcurrentQueue<CancellationToken>();
@@ -785,7 +766,6 @@ await Parallel.ForEachAsync(Enumerable.Range(1, 100), async (item, cancellationT
         }
 
         [ConditionalFact(typeof(PlatformDetection), nameof(PlatformDetection.IsThreadingSupported))]
-        [ActiveIssue("https://github.com/dotnet/runtime/issues/91538", typeof(PlatformDetection), nameof(PlatformDetection.IsWasmThreadingSupported))]
         public async Task Cancellation_SameTokenPassedToEveryInvocation_Async()
         {
             var cq = new ConcurrentQueue<CancellationToken>();
@@ -801,7 +781,6 @@ await Parallel.ForEachAsync(EnumerableRangeAsync(1, 100), async (item, cancellat
         }
 
         [ConditionalFact(typeof(PlatformDetection), nameof(PlatformDetection.IsThreadingSupported))]
-        [ActiveIssue("https://github.com/dotnet/runtime/issues/91538", typeof(PlatformDetection), nameof(PlatformDetection.IsWasmThreadingSupported))]
         public async Task Cancellation_HasPriorityOverExceptions_For()
         {
             var tcs = new TaskCompletionSource();
@@ -828,7 +807,6 @@ public async Task Cancellation_HasPriorityOverExceptions_For()
         }
 
         [ConditionalFact(typeof(PlatformDetection), nameof(PlatformDetection.IsThreadingSupported))]
-        [ActiveIssue("https://github.com/dotnet/runtime/issues/91538", typeof(PlatformDetection), nameof(PlatformDetection.IsWasmThreadingSupported))]
         public async Task Cancellation_HasPriorityOverExceptions_Sync()
         {
             static IEnumerable<int> Iterate()
@@ -861,7 +839,6 @@ static IEnumerable<int> Iterate()
         }
 
         [ConditionalFact(typeof(PlatformDetection), nameof(PlatformDetection.IsThreadingSupported))]
-        [ActiveIssue("https://github.com/dotnet/runtime/issues/91538", typeof(PlatformDetection), nameof(PlatformDetection.IsWasmThreadingSupported))]
         public async Task Cancellation_HasPriorityOverExceptions_Async()
         {
             static async IAsyncEnumerable<int> Iterate()
@@ -898,7 +875,6 @@ static async IAsyncEnumerable<int> Iterate()
         }
 
         [ConditionalTheory(typeof(PlatformDetection), nameof(PlatformDetection.IsThreadingSupported))]
-        [ActiveIssue("https://github.com/dotnet/runtime/issues/91538", typeof(PlatformDetection), nameof(PlatformDetection.IsWasmThreadingSupported))]
         [InlineData(false)]
         [InlineData(true)]
         public async Task Cancellation_FaultsForOceForNonCancellation_For(bool internalToken)
@@ -915,7 +891,6 @@ public async Task Cancellation_FaultsForOceForNonCancellation_For(bool internalT
         }
 
         [ConditionalTheory(typeof(PlatformDetection), nameof(PlatformDetection.IsThreadingSupported))]
-        [ActiveIssue("https://github.com/dotnet/runtime/issues/91538", typeof(PlatformDetection), nameof(PlatformDetection.IsWasmThreadingSupported))]
         [InlineData(false)]
         [InlineData(true)]
         public async Task Cancellation_FaultsForOceForNonCancellation(bool internalToken)
@@ -942,7 +917,6 @@ static async IAsyncEnumerable<int> Iterate()
         }
 
         [ConditionalTheory(typeof(PlatformDetection), nameof(PlatformDetection.IsThreadingSupported))]
-        [ActiveIssue("https://github.com/dotnet/runtime/issues/91538", typeof(PlatformDetection), nameof(PlatformDetection.IsWasmThreadingSupported))]
         [InlineData(0, 4)]
         [InlineData(1, 4)]
         [InlineData(2, 4)]
@@ -975,7 +949,6 @@ public async Task Cancellation_InternalCancellationExceptionsArentFilteredOut_Fo
         }
 
         [ConditionalTheory(typeof(PlatformDetection), nameof(PlatformDetection.IsThreadingSupported))]
-        [ActiveIssue("https://github.com/dotnet/runtime/issues/91538", typeof(PlatformDetection), nameof(PlatformDetection.IsWasmThreadingSupported))]
         [InlineData(0, 4)]
         [InlineData(1, 4)]
         [InlineData(2, 4)]
@@ -1008,7 +981,6 @@ public async Task Cancellation_InternalCancellationExceptionsArentFilteredOut(in
         }
 
         [ConditionalFact(typeof(PlatformDetection), nameof(PlatformDetection.IsThreadingSupported))]
-        [ActiveIssue("https://github.com/dotnet/runtime/issues/91538", typeof(PlatformDetection), nameof(PlatformDetection.IsWasmThreadingSupported))]
         public void Exception_FromGetEnumerator_Sync()
         {
             Task t = Parallel.ForEachAsync((IEnumerable<int>)new ThrowsFromGetEnumerator(), (item, cancellationToken) => default);
@@ -1018,7 +990,6 @@ public void Exception_FromGetEnumerator_Sync()
         }
 
         [ConditionalFact(typeof(PlatformDetection), nameof(PlatformDetection.IsThreadingSupported))]
-        [ActiveIssue("https://github.com/dotnet/runtime/issues/91538", typeof(PlatformDetection), nameof(PlatformDetection.IsWasmThreadingSupported))]
         public void Exception_FromGetEnumerator_Async()
         {
             Task t = Parallel.ForEachAsync((IAsyncEnumerable<int>)new ThrowsFromGetEnumerator(), (item, cancellationToken) => default);
@@ -1028,7 +999,6 @@ public void Exception_FromGetEnumerator_Async()
         }
 
         [ConditionalFact(typeof(PlatformDetection), nameof(PlatformDetection.IsThreadingSupported))]
-        [ActiveIssue("https://github.com/dotnet/runtime/issues/91538", typeof(PlatformDetection), nameof(PlatformDetection.IsWasmThreadingSupported))]
         public void Exception_NullFromGetEnumerator_Sync()
         {
             Task t = Parallel.ForEachAsync((IEnumerable<int>)new ReturnsNullFromGetEnumerator(), (item, cancellationToken) => default);
@@ -1038,7 +1008,6 @@ public void Exception_NullFromGetEnumerator_Sync()
         }
 
         [ConditionalFact(typeof(PlatformDetection), nameof(PlatformDetection.IsThreadingSupported))]
-        [ActiveIssue("https://github.com/dotnet/runtime/issues/91538", typeof(PlatformDetection), nameof(PlatformDetection.IsWasmThreadingSupported))]
         public void Exception_NullFromGetEnumerator_Async()
         {
             Task t = Parallel.ForEachAsync((IAsyncEnumerable<int>)new ReturnsNullFromGetEnumerator(), (item, cancellationToken) => default);
@@ -1048,7 +1017,6 @@ public void Exception_NullFromGetEnumerator_Async()
         }
 
         [ConditionalFact(typeof(PlatformDetection), nameof(PlatformDetection.IsThreadingSupported))]
-        [ActiveIssue("https://github.com/dotnet/runtime/issues/91538", typeof(PlatformDetection), nameof(PlatformDetection.IsWasmThreadingSupported))]
         public async Task Exception_FromMoveNext_Sync()
         {
             static IEnumerable<int> Iterate()
@@ -1069,7 +1037,6 @@ static IEnumerable<int> Iterate()
         }
 
         [ConditionalFact(typeof(PlatformDetection), nameof(PlatformDetection.IsThreadingSupported))]
-        [ActiveIssue("https://github.com/dotnet/runtime/issues/91538", typeof(PlatformDetection), nameof(PlatformDetection.IsWasmThreadingSupported))]
         public async Task Exception_FromMoveNext_Async()
         {
             static async IAsyncEnumerable<int> Iterate()
@@ -1091,7 +1058,6 @@ static async IAsyncEnumerable<int> Iterate()
         }
 
         [ConditionalFact(typeof(PlatformDetection), nameof(PlatformDetection.IsThreadingSupported))]
-        [ActiveIssue("https://github.com/dotnet/runtime/issues/91538", typeof(PlatformDetection), nameof(PlatformDetection.IsWasmThreadingSupported))]
         public async Task Exception_FromLoopBody_For()
         {
             var barrier = new Barrier(2);
@@ -1113,7 +1079,6 @@ public async Task Exception_FromLoopBody_For()
         }
 
         [ConditionalFact(typeof(PlatformDetection), nameof(PlatformDetection.IsThreadingSupported))]
-        [ActiveIssue("https://github.com/dotnet/runtime/issues/91538", typeof(PlatformDetection), nameof(PlatformDetection.IsWasmThreadingSupported))]
         public async Task Exception_FromLoopBody_Sync()
         {
             static IEnumerable<int> Iterate()
@@ -1141,7 +1106,6 @@ static IEnumerable<int> Iterate()
         }
 
         [ConditionalFact(typeof(PlatformDetection), nameof(PlatformDetection.IsThreadingSupported))]
-        [ActiveIssue("https://github.com/dotnet/runtime/issues/91538", typeof(PlatformDetection), nameof(PlatformDetection.IsWasmThreadingSupported))]
         public async Task Exception_FromLoopBody_Async()
         {
             static async IAsyncEnumerable<int> Iterate()
@@ -1183,7 +1147,6 @@ static async IAsyncEnumerable<int> Iterate()
         }
 
         [ConditionalFact(typeof(PlatformDetection), nameof(PlatformDetection.IsThreadingSupported))]
-        [ActiveIssue("https://github.com/dotnet/runtime/issues/91538", typeof(PlatformDetection), nameof(PlatformDetection.IsWasmThreadingSupported))]
         public async Task Exception_FromDispose_Sync()
         {
             Task t = Parallel.ForEachAsync((IEnumerable<int>)new ThrowsExceptionFromDispose(), (item, cancellationToken) => default);
@@ -1192,7 +1155,6 @@ public async Task Exception_FromDispose_Sync()
         }
 
         [ConditionalFact(typeof(PlatformDetection), nameof(PlatformDetection.IsThreadingSupported))]
-        [ActiveIssue("https://github.com/dotnet/runtime/issues/91538", typeof(PlatformDetection), nameof(PlatformDetection.IsWasmThreadingSupported))]
         public async Task Exception_FromDispose_Async()
         {
             Task t = Parallel.ForEachAsync((IAsyncEnumerable<int>)new ThrowsExceptionFromDispose(), (item, cancellationToken) => default);
@@ -1201,7 +1163,6 @@ public async Task Exception_FromDispose_Async()
         }
 
         [ConditionalFact(typeof(PlatformDetection), nameof(PlatformDetection.IsThreadingSupported))]
-        [ActiveIssue("https://github.com/dotnet/runtime/issues/91538", typeof(PlatformDetection), nameof(PlatformDetection.IsWasmThreadingSupported))]
         public async Task Exception_FromDisposeAndCancellationCallback_Sync()
         {
             Task t = Parallel.ForEachAsync((IEnumerable<int>)new ThrowsExceptionFromDisposeAndCancellationCallback(), (item, cancellationToken) => default);
@@ -1211,7 +1172,6 @@ public async Task Exception_FromDisposeAndCancellationCallback_Sync()
         }
 
         [ConditionalFact(typeof(PlatformDetection), nameof(PlatformDetection.IsThreadingSupported))]
-        [ActiveIssue("https://github.com/dotnet/runtime/issues/91538", typeof(PlatformDetection), nameof(PlatformDetection.IsWasmThreadingSupported))]
         public async Task Exception_FromDisposeAndCancellationCallback_Async()
         {
             Task t = Parallel.ForEachAsync((IAsyncEnumerable<int>)new ThrowsExceptionFromDisposeAndCancellationCallback(), (item, cancellationToken) => default);
@@ -1221,7 +1181,6 @@ public async Task Exception_FromDisposeAndCancellationCallback_Async()
         }
 
         [ConditionalFact(typeof(PlatformDetection), nameof(PlatformDetection.IsThreadingSupported))]
-        [ActiveIssue("https://github.com/dotnet/runtime/issues/91538", typeof(PlatformDetection), nameof(PlatformDetection.IsWasmThreadingSupported))]
         public async Task Exception_ImplicitlyCancelsOtherWorkers_For()
         {
             await Assert.ThrowsAsync<Exception>(() => Parallel.ForAsync(0, long.MaxValue, async (item, cancellationToken) =>
@@ -1250,7 +1209,6 @@ await Assert.ThrowsAsync<Exception>(() => Parallel.ForAsync(0, long.MaxValue, as
         }
 
         [ConditionalFact(typeof(PlatformDetection), nameof(PlatformDetection.IsThreadingSupported))]
-        [ActiveIssue("https://github.com/dotnet/runtime/issues/91538", typeof(PlatformDetection), nameof(PlatformDetection.IsWasmThreadingSupported))]
         public async Task Exception_ImplicitlyCancelsOtherWorkers_Sync()
         {
             static IEnumerable<int> Iterate()
@@ -1356,7 +1314,6 @@ static async IAsyncEnumerable<int> Iterate(Task signal)
         }
 
         [ConditionalTheory(typeof(PlatformDetection), nameof(PlatformDetection.IsThreadingSupported))]
-        [ActiveIssue("https://github.com/dotnet/runtime/issues/91538", typeof(PlatformDetection), nameof(PlatformDetection.IsWasmThreadingSupported))]
         [InlineData(false)]
         [InlineData(true)]
         public async Task ExecutionContext_FlowsToWorkerBodies_For(bool defaultScheduler)
@@ -1375,7 +1332,6 @@ await Parallel.ForAsync(0, 100, async (item, cancellationToken) =>
         }
 
         [ConditionalTheory(typeof(PlatformDetection), nameof(PlatformDetection.IsThreadingSupported))]
-        [ActiveIssue("https://github.com/dotnet/runtime/issues/91538", typeof(PlatformDetection), nameof(PlatformDetection.IsWasmThreadingSupported))]
         [InlineData(false)]
         [InlineData(true)]
         public async Task ExecutionContext_FlowsToWorkerBodies_Sync(bool defaultScheduler)
diff --git a/src/libraries/System.Threading.Tasks.Parallel/tests/ParallelForTests.cs b/src/libraries/System.Threading.Tasks.Parallel/tests/ParallelForTests.cs
index 39f1e2bb49822d..7ae7693fb20310 100644
--- a/src/libraries/System.Threading.Tasks.Parallel/tests/ParallelForTests.cs
+++ b/src/libraries/System.Threading.Tasks.Parallel/tests/ParallelForTests.cs
@@ -289,7 +289,6 @@ public static void RunSimpleParallelDoTest(int increms)
         [InlineData(1024)]
         [InlineData(1024 * 1024)]
         [InlineData(1024 * 1024 * 16)]
-        [ActiveIssue("https://github.com/dotnet/runtime/issues/91538", typeof(PlatformDetection), nameof(PlatformDetection.IsWasmThreadingSupported))]
         public static void RunSimpleParallelForIncrementTest(int increms)
         {
             // Just increments a shared counter in a loop.
@@ -320,7 +319,6 @@ public static void RunSimpleParallelForIncrementTest(int increms)
         }
 
         [ConditionalTheory(typeof(PlatformDetection), nameof(PlatformDetection.IsThreadingSupported))]
-        [ActiveIssue("https://github.com/dotnet/runtime/issues/91538", typeof(PlatformDetection), nameof(PlatformDetection.IsWasmThreadingSupported))]
         [InlineData(-1)]
         [InlineData(0)]
         [InlineData(1)]
@@ -454,7 +452,6 @@ public static void SequentialFor64ParityTest(long inclusiveFrom, long exclusiveT
         }
 
         [ConditionalTheory(typeof(PlatformDetection), nameof(PlatformDetection.IsThreadingSupported))]
-        [ActiveIssue("https://github.com/dotnet/runtime/issues/91538", typeof(PlatformDetection), nameof(PlatformDetection.IsWasmThreadingSupported))]
         [InlineData(0)]
         [InlineData(1)]
         [InlineData(1024)]
@@ -484,7 +481,6 @@ public static void RunSimpleParallelForeachAddTest_Enumerable(int count)
         }
 
         [ConditionalTheory(typeof(PlatformDetection), nameof(PlatformDetection.IsThreadingSupported))]
-        [ActiveIssue("https://github.com/dotnet/runtime/issues/91538", typeof(PlatformDetection), nameof(PlatformDetection.IsWasmThreadingSupported))]
         [InlineData(0)]
         [InlineData(1)]
         [InlineData(1024)]
@@ -515,7 +511,6 @@ public static void RunSimpleParallelForeachAddTest_List(int count)
         }
 
         [ConditionalTheory(typeof(PlatformDetection), nameof(PlatformDetection.IsThreadingSupported))]
-        [ActiveIssue("https://github.com/dotnet/runtime/issues/91538", typeof(PlatformDetection), nameof(PlatformDetection.IsWasmThreadingSupported))]
         [InlineData(0)]
         [InlineData(1)]
         [InlineData(1024)]
@@ -546,7 +541,6 @@ public static void RunSimpleParallelForeachAddTest_Array(int count)
         }
 
         [ConditionalTheory(typeof(PlatformDetection), nameof(PlatformDetection.IsThreadingSupported))]
-        [ActiveIssue("https://github.com/dotnet/runtime/issues/91538", typeof(PlatformDetection), nameof(PlatformDetection.IsWasmThreadingSupported))]
         [InlineData(0)]
         [InlineData(1)]
         [InlineData(1024)]
@@ -578,7 +572,6 @@ public static void RunSimpleParallelForAverageAggregation(int count)
         }
 
         [ConditionalTheory(typeof(PlatformDetection), nameof(PlatformDetection.IsThreadingSupported))]
-        [ActiveIssue("https://github.com/dotnet/runtime/issues/91538", typeof(PlatformDetection), nameof(PlatformDetection.IsWasmThreadingSupported))]
         [InlineData(0)]
         [InlineData(1)]
         [InlineData(1024)]
@@ -718,7 +711,6 @@ public static void TestParallelForDOP()
         }
 
         [ConditionalFact(typeof(PlatformDetection), nameof(PlatformDetection.IsThreadingSupported))]
-        [ActiveIssue("https://github.com/dotnet/runtime/issues/91538", typeof(PlatformDetection), nameof(PlatformDetection.IsWasmThreadingSupported))]
         public static void TestParallelForPaths()
         {
             int loopsize = 1000;
@@ -880,7 +872,6 @@ public static void TestParallelForPaths()
         }
 
         [Fact]
-        [ActiveIssue("https://github.com/dotnet/runtime/issues/91538", typeof(PlatformDetection), nameof(PlatformDetection.IsWasmThreadingSupported))]
         public static void TestParallelForPaths_Exceptions()
         {
             int loopsize = 1000;
@@ -1120,7 +1111,6 @@ public static void TestInvokeDOPAndCancel()
         }
 
         [Fact]
-        [ActiveIssue("https://github.com/dotnet/runtime/issues/91538", typeof(PlatformDetection), nameof(PlatformDetection.IsWasmThreadingSupported))]
         public static void RunParallelLoopCancellationTests()
         {
             int counter = 0; // Counts the actual number of iterations
@@ -1255,7 +1245,6 @@ private static void VerifyCancelTestState(
         }
 
         [ConditionalFact(typeof(PlatformDetection), nameof(PlatformDetection.IsThreadingSupported))]
-        [ActiveIssue("https://github.com/dotnet/runtime/issues/91538", typeof(PlatformDetection), nameof(PlatformDetection.IsWasmThreadingSupported))]
         public static void CancelForIntTest()
         {
             for (int i = 0; i < 100; ++i)
@@ -1290,7 +1279,6 @@ public static void CancelForIntTest()
         }
 
         [ConditionalFact(typeof(PlatformDetection), nameof(PlatformDetection.IsThreadingSupported))]
-        [ActiveIssue("https://github.com/dotnet/runtime/issues/91538", typeof(PlatformDetection), nameof(PlatformDetection.IsWasmThreadingSupported))]
         public static void CancelForLongTest()
         {
             for (int i = 0; i < 100; ++i)
@@ -1332,7 +1320,6 @@ public static IEnumerable<object[]> CancelForEachTest_MemberData()
         }
 
         [ConditionalTheory(typeof(PlatformDetection), nameof(PlatformDetection.IsThreadingSupported))]
-        [ActiveIssue("https://github.com/dotnet/runtime/issues/91538", typeof(PlatformDetection), nameof(PlatformDetection.IsWasmThreadingSupported))]
         [MemberData(nameof(CancelForEachTest_MemberData))]
         public static void CancelForEachTest(IEnumerable<int> enumerable)
         {
