diff --git a/doc/requirements.txt b/doc/requirements.txt
index 87e497a58e..5af2b45239 100644
--- a/doc/requirements.txt
+++ b/doc/requirements.txt
@@ -2,7 +2,7 @@
 # of appearance. Changing the order has an impact on the overall integration
 # process, which may cause wedges in the gate later.
 sphinx!=1.6.6,!=1.6.7,>=1.6.2,<2.0.0;python_version=='2.7' # BSD
-sphinx!=1.6.6,!=1.6.7,>=1.6.2;python_version>='3.4' # BSD
+sphinx!=1.6.6,!=1.6.7,!=2.1.0,>=1.6.2;python_version>='3.4' # BSD
 os-api-ref>=1.4.0 # Apache-2.0
 openstackdocstheme>=1.18.1 # Apache-2.0
 reno>=2.5.0 # Apache-2.0
diff --git a/test-requirements.txt b/test-requirements.txt
index 373efd3ef3..181828d6bd 100644
--- a/test-requirements.txt
+++ b/test-requirements.txt
@@ -14,7 +14,7 @@ ddt>=1.0.1 # MIT
 fixtures>=3.0.0 # Apache-2.0/BSD
 mock>=2.0.0 # BSD
 sphinx!=1.6.6,!=1.6.7,>=1.6.2,<2.0.0;python_version=='2.7' # BSD
-sphinx!=1.6.6,!=1.6.7,>=1.6.2;python_version>='3.4' # BSD
+sphinx!=1.6.6,!=1.6.7,!=2.1.0,>=1.6.2;python_version>='3.4' # BSD
 requests>=2.14.2 # Apache-2.0
 testrepository>=0.0.18 # Apache-2.0/BSD
 testresources>=2.0.0 # Apache-2.0/BSD