diff --git a/bigquery/setup.py b/bigquery/setup.py
index 82a9e42d3458..36b000fec6d2 100644
--- a/bigquery/setup.py
+++ b/bigquery/setup.py
@@ -50,7 +50,7 @@
 
 
 REQUIREMENTS = [
-    'google-cloud-core >= 0.21.0',
+    'google-cloud-core >= 0.21.0, < 0.22dev',
 ]
 
 setup(
diff --git a/bigtable/setup.py b/bigtable/setup.py
index 2f4fe451fb28..a5e7387ac813 100644
--- a/bigtable/setup.py
+++ b/bigtable/setup.py
@@ -50,7 +50,7 @@
 
 
 REQUIREMENTS = [
-    'google-cloud-core >= 0.21.0',
+    'google-cloud-core >= 0.21.0, < 0.22dev',
     'grpcio >= 1.0.0, < 2.0dev',
 ]
 
diff --git a/datastore/setup.py b/datastore/setup.py
index b1884e3c69eb..e79548d09a58 100644
--- a/datastore/setup.py
+++ b/datastore/setup.py
@@ -50,7 +50,7 @@
 
 
 REQUIREMENTS = [
-    'google-cloud-core >= 0.21.0',
+    'google-cloud-core >= 0.21.0, < 0.22dev',
     'grpcio >= 1.0.0, < 2.0dev',
 ]
 
diff --git a/dns/setup.py b/dns/setup.py
index fd3360e80828..a66924a04700 100644
--- a/dns/setup.py
+++ b/dns/setup.py
@@ -50,7 +50,7 @@
 
 
 REQUIREMENTS = [
-    'google-cloud-core >= 0.21.0',
+    'google-cloud-core >= 0.21.0, < 0.22dev',
 ]
 
 setup(
diff --git a/error_reporting/setup.py b/error_reporting/setup.py
index 44024cf4b059..a3e646f1b917 100644
--- a/error_reporting/setup.py
+++ b/error_reporting/setup.py
@@ -50,7 +50,7 @@
 
 
 REQUIREMENTS = [
-    'google-cloud-core >= 0.21.0',
+    'google-cloud-core >= 0.21.0, < 0.22dev',
     'google-cloud-logging >= 0.21.0',
 ]
 
diff --git a/language/setup.py b/language/setup.py
index 49ca5d60e788..4c1d2f134f34 100644
--- a/language/setup.py
+++ b/language/setup.py
@@ -50,7 +50,7 @@
 
 
 REQUIREMENTS = [
-    'google-cloud-core >= 0.21.0',
+    'google-cloud-core >= 0.21.0, < 0.22dev',
 ]
 
 setup(
diff --git a/logging/setup.py b/logging/setup.py
index 6ab0c59b6ca0..1a335fcf6760 100644
--- a/logging/setup.py
+++ b/logging/setup.py
@@ -50,7 +50,7 @@
 
 
 REQUIREMENTS = [
-    'google-cloud-core >= 0.21.0',
+    'google-cloud-core >= 0.21.0, < 0.22dev',
     'grpcio >= 1.0.0, < 2.0dev',
     'google-gax >= 0.14.1, < 0.15dev',
     'gapic-google-logging-v2 >= 0.10.1, < 0.11dev',
diff --git a/monitoring/setup.py b/monitoring/setup.py
index 44f14e2c1327..c33132b848c2 100644
--- a/monitoring/setup.py
+++ b/monitoring/setup.py
@@ -50,7 +50,7 @@
 
 
 REQUIREMENTS = [
-    'google-cloud-core >= 0.21.0',
+    'google-cloud-core >= 0.21.0, < 0.22dev',
 ]
 
 setup(
diff --git a/pubsub/setup.py b/pubsub/setup.py
index eb6b58cb86a0..c206a94991ed 100644
--- a/pubsub/setup.py
+++ b/pubsub/setup.py
@@ -50,7 +50,7 @@
 
 
 REQUIREMENTS = [
-    'google-cloud-core >= 0.21.0',
+    'google-cloud-core >= 0.21.0, < 0.22dev',
     'grpcio >= 1.0.0, < 2.0dev',
     'google-gax >= 0.14.1, < 0.15dev',
     'gapic-google-pubsub-v1 >= 0.10.1, < 0.11dev',
diff --git a/resource_manager/setup.py b/resource_manager/setup.py
index 0bc3e55ec04e..6f2b838261c0 100644
--- a/resource_manager/setup.py
+++ b/resource_manager/setup.py
@@ -50,7 +50,7 @@
 
 
 REQUIREMENTS = [
-    'google-cloud-core >= 0.21.0',
+    'google-cloud-core >= 0.21.0, < 0.22dev',
 ]
 
 setup(
diff --git a/runtimeconfig/setup.py b/runtimeconfig/setup.py
index 86abf32de4be..410fe433be7a 100644
--- a/runtimeconfig/setup.py
+++ b/runtimeconfig/setup.py
@@ -50,7 +50,7 @@
 
 
 REQUIREMENTS = [
-    'google-cloud-core >= 0.21.0',
+    'google-cloud-core >= 0.21.0, < 0.22dev',
 ]
 
 setup(
diff --git a/storage/setup.py b/storage/setup.py
index 7a877b07b37b..adc96a1d2c50 100644
--- a/storage/setup.py
+++ b/storage/setup.py
@@ -50,7 +50,7 @@
 
 
 REQUIREMENTS = [
-    'google-cloud-core >= 0.21.0',
+    'google-cloud-core >= 0.21.0, < 0.22dev',
 ]
 
 setup(
diff --git a/translate/setup.py b/translate/setup.py
index 8245c14cc00c..63ce5117f12a 100644
--- a/translate/setup.py
+++ b/translate/setup.py
@@ -50,7 +50,7 @@
 
 
 REQUIREMENTS = [
-    'google-cloud-core >= 0.21.0',
+    'google-cloud-core >= 0.21.0, < 0.22dev',
 ]
 
 setup(
diff --git a/vision/setup.py b/vision/setup.py
index 29e83cc6cf64..b9ee28770610 100644
--- a/vision/setup.py
+++ b/vision/setup.py
@@ -50,7 +50,7 @@
 
 
 REQUIREMENTS = [
-    'google-cloud-core >= 0.21.0',
+    'google-cloud-core >= 0.21.0, < 0.22dev',
 ]
 
 setup(