diff --git a/requirements-dev.txt b/requirements-dev.txt
index b19fc2e01..27b71a268 100644
--- a/requirements-dev.txt
+++ b/requirements-dev.txt
@@ -1,6 +1,6 @@
 coverage==4.4.2
 ddt==1.2.0
 flake8==3.5.0
-mock==2.0.0
+mock==3.0.5
 pytest==3.6.3
 pytest-cov==2.5.1
diff --git a/setup.py b/setup.py
index 614478010..4ceb6e1f8 100644
--- a/setup.py
+++ b/setup.py
@@ -49,7 +49,7 @@ tests_require = [
 
 
 if sys.version_info[:2] < (3, 4):
-    tests_require.append('mock >= 1.0.1, < 2')
+    tests_require.append('mock >= 1.0.1, < 4')
 
 extras_require = {
     ':python_version < "3.4"': ['enum34 >= 1.0.4, < 2'],