diff --git a/asset/setup.py b/asset/setup.py
index 50d920c71304..4222c491b574 100644
--- a/asset/setup.py
+++ b/asset/setup.py
@@ -30,7 +30,7 @@
 dependencies = [
     "google-api-core[grpc] >= 1.6.0, < 2.0.0dev",
     'enum34; python_version < "3.4"',
-    "grpc-google-iam-v1 >= 0.11.4, < 0.12dev",
+    "grpc-google-iam-v1 >= 0.12.3, < 0.13dev",
 ]
 
 # Setup boilerplate below this line.
diff --git a/bigtable/setup.py b/bigtable/setup.py
index 028a2030212b..b2dce3ca9767 100644
--- a/bigtable/setup.py
+++ b/bigtable/setup.py
@@ -31,7 +31,7 @@
 dependencies = [
     'google-api-core[grpc] >= 1.6.0, < 2.0.0dev',
     "google-cloud-core >= 1.0.0, < 2.0dev",
-    'grpc-google-iam-v1 >= 0.11.4, < 0.12dev',
+    "grpc-google-iam-v1 >= 0.12.3, < 0.13dev",
 ]
 extras = {
 }
diff --git a/container/setup.py b/container/setup.py
index f512d6e192e6..ccdabb325aad 100644
--- a/container/setup.py
+++ b/container/setup.py
@@ -30,7 +30,7 @@
 release_status = "Development Status :: 3 - Alpha"
 dependencies = [
     "google-api-core[grpc] >= 1.6.0, < 2.0.0dev",
-    "grpc-google-iam-v1 >= 0.11.4, < 0.12dev",
+    "grpc-google-iam-v1 >= 0.12.3, < 0.13dev",
 ]
 extras = {}
 
diff --git a/containeranalysis/setup.py b/containeranalysis/setup.py
index b4c90a0d2138..03e107fc1a11 100644
--- a/containeranalysis/setup.py
+++ b/containeranalysis/setup.py
@@ -26,7 +26,7 @@
 release_status = "Development Status :: 3 - Alpha"
 dependencies = [
     "google-api-core[grpc] >= 1.4.1, < 2.0.0dev",
-    "grpc-google-iam-v1 >= 0.11.1, < 0.12dev",
+    "grpc-google-iam-v1 >= 0.12.3, < 0.13dev",
     'enum34; python_version < "3.4"',
     "grafeas",
 ]
diff --git a/datacatalog/setup.py b/datacatalog/setup.py
index 2981e2dbba58..0ad7555d0a91 100644
--- a/datacatalog/setup.py
+++ b/datacatalog/setup.py
@@ -29,7 +29,7 @@
 release_status = "Development Status :: 3 - Alpha"
 dependencies = [
     "google-api-core[grpc] >= 1.4.1, < 2.0.0dev",
-    "grpc-google-iam-v1 >= 0.11.4, < 0.12dev",
+    "grpc-google-iam-v1 >= 0.12.3, < 0.13dev",
     'enum34; python_version < "3.4"',
 ]
 
diff --git a/iot/setup.py b/iot/setup.py
index 0206a44e1431..55807517d8c4 100644
--- a/iot/setup.py
+++ b/iot/setup.py
@@ -23,7 +23,7 @@
 release_status = "Development Status :: 3 - Alpha"
 dependencies = [
     "google-api-core[grpc] >= 1.6.0, < 2.0.0dev",
-    "grpc-google-iam-v1 >= 0.11.4, < 0.12dev",
+    "grpc-google-iam-v1 >= 0.12.3, < 0.13dev",
     'enum34; python_version < "3.4"',
 ]
 
diff --git a/kms/google/cloud/kms_v1/gapic/transports/key_management_service_grpc_transport.py b/kms/google/cloud/kms_v1/gapic/transports/key_management_service_grpc_transport.py
index 59f1576c0c0b..52dfd68581e4 100644
--- a/kms/google/cloud/kms_v1/gapic/transports/key_management_service_grpc_transport.py
+++ b/kms/google/cloud/kms_v1/gapic/transports/key_management_service_grpc_transport.py
@@ -18,7 +18,7 @@
 import google.api_core.grpc_helpers
 
 from google.cloud.kms_v1.proto import service_pb2_grpc
-from google.iam.v1 import iam_policy_pb2
+from google.iam.v1 import iam_policy_pb2_grpc as iam_policy_pb2
 
 
 class KeyManagementServiceGrpcTransport(object):
diff --git a/kms/setup.py b/kms/setup.py
index f3a1d7c71662..e53a9748b029 100644
--- a/kms/setup.py
+++ b/kms/setup.py
@@ -25,7 +25,7 @@
 release_status = "Development Status :: 5 - Production/Stable"
 dependencies = [
     "google-api-core[grpc] >= 1.6.0, < 2.0.0dev",
-    "grpc-google-iam-v1 >= 0.11.4, < 0.12dev",
+    "grpc-google-iam-v1 >= 0.12.3, < 0.13dev",
     'enum34; python_version < "3.4"',
 ]
 
diff --git a/kms/synth.py b/kms/synth.py
index c216ae7b85f1..e1570a7284e0 100644
--- a/kms/synth.py
+++ b/kms/synth.py
@@ -39,6 +39,13 @@
 
 s.move(library, excludes=["README.rst", "setup.py", "nox*.py", "docs/**/*"])
 
+# Temporary fixup for 'grpc-google-iam-vi 0.12.4' (before generation).
+s.replace(
+    "google/cloud/kms_v1/gapic/transports/key_management_service_grpc_transport.py",
+    "from google.iam.v1 import iam_policy_pb2",
+    "from google.iam.v1 import iam_policy_pb2_grpc as iam_policy_pb2",
+)
+
 # ----------------------------------------------------------------------------
 # Add templated files
 # ----------------------------------------------------------------------------
diff --git a/pubsub/google/cloud/pubsub_v1/gapic/transports/publisher_grpc_transport.py b/pubsub/google/cloud/pubsub_v1/gapic/transports/publisher_grpc_transport.py
index 38ecea168903..2a5c38104b3b 100644
--- a/pubsub/google/cloud/pubsub_v1/gapic/transports/publisher_grpc_transport.py
+++ b/pubsub/google/cloud/pubsub_v1/gapic/transports/publisher_grpc_transport.py
@@ -18,7 +18,7 @@
 import google.api_core.grpc_helpers
 
 from google.cloud.pubsub_v1.proto import pubsub_pb2_grpc
-from google.iam.v1 import iam_policy_pb2
+from google.iam.v1 import iam_policy_pb2_grpc as iam_policy_pb2
 
 
 class PublisherGrpcTransport(object):
diff --git a/pubsub/google/cloud/pubsub_v1/gapic/transports/subscriber_grpc_transport.py b/pubsub/google/cloud/pubsub_v1/gapic/transports/subscriber_grpc_transport.py
index 794575b5551d..16c1f82d0f30 100644
--- a/pubsub/google/cloud/pubsub_v1/gapic/transports/subscriber_grpc_transport.py
+++ b/pubsub/google/cloud/pubsub_v1/gapic/transports/subscriber_grpc_transport.py
@@ -18,7 +18,7 @@
 import google.api_core.grpc_helpers
 
 from google.cloud.pubsub_v1.proto import pubsub_pb2_grpc
-from google.iam.v1 import iam_policy_pb2
+from google.iam.v1 import iam_policy_pb2_grpc as iam_policy_pb2
 
 
 class SubscriberGrpcTransport(object):
diff --git a/pubsub/setup.py b/pubsub/setup.py
index 6edb02352d35..df05565bb5e9 100644
--- a/pubsub/setup.py
+++ b/pubsub/setup.py
@@ -30,7 +30,7 @@
 release_status = "Development Status :: 4 - Beta"
 dependencies = [
     "google-api-core[grpc] >= 1.12.0, < 2.0.0dev",
-    "grpc-google-iam-v1 >= 0.11.4, < 0.12dev",
+    "grpc-google-iam-v1 >= 0.12.3, < 0.13dev",
     'enum34; python_version < "3.4"',
 ]
 extras = {}
diff --git a/pubsub/synth.py b/pubsub/synth.py
index f95da65ede0c..c4601afbdb51 100644
--- a/pubsub/synth.py
+++ b/pubsub/synth.py
@@ -167,6 +167,13 @@ def _merge_dict(d1, d2):
     """
 )
 
+# Temporary fixup for 'grpc-google-iam-vi 0.12.4' (before generation).
+s.replace(
+    "google/cloud/pubsub_v1/gapic/transports/*_grpc_transport.py",
+    "from google.iam.v1 import iam_policy_pb2",
+    "from google.iam.v1 import iam_policy_pb2_grpc as iam_policy_pb2",
+)
+
 # ----------------------------------------------------------------------------
 # Add templated files
 # ----------------------------------------------------------------------------
diff --git a/securitycenter/setup.py b/securitycenter/setup.py
index 7c52a286c0c8..151afca7c6a9 100644
--- a/securitycenter/setup.py
+++ b/securitycenter/setup.py
@@ -25,7 +25,7 @@
 release_status = 'Development Status :: 3 - Alpha'
 dependencies = [
     'google-api-core[grpc] >= 1.6.0, < 2.0.0dev',
-    'grpc-google-iam-v1 >= 0.11.4, < 0.12dev',
+    'grpc-google-iam-v1 >= 0.12.3, < 0.13dev',
     'enum34; python_version < "3.4"',
 ]
 
diff --git a/spanner/setup.py b/spanner/setup.py
index d343a7d349ed..fe8723aad249 100644
--- a/spanner/setup.py
+++ b/spanner/setup.py
@@ -31,7 +31,7 @@
 dependencies = [
     "google-api-core[grpc, grpcgcp] >= 1.4.1, < 2.0.0dev",
     "google-cloud-core >= 1.0.0, < 2.0dev",
-    "grpc-google-iam-v1 >= 0.11.4, < 0.12dev",
+    "grpc-google-iam-v1 >= 0.12.3, < 0.13dev",
 ]
 extras = {}
 
diff --git a/tasks/setup.py b/tasks/setup.py
index 3cc15b212f73..6aa52e5bc975 100644
--- a/tasks/setup.py
+++ b/tasks/setup.py
@@ -25,7 +25,7 @@
 release_status = "Development Status :: 5 - Production/Stable"
 dependencies = [
     "google-api-core[grpc] >= 1.6.0, < 2.0.0dev",
-    "grpc-google-iam-v1 >= 0.11.4, < 0.12dev",
+    "grpc-google-iam-v1 >= 0.12.3, < 0.13dev",
     'enum34; python_version < "3.4"',
 ]
 
