diff --git a/requirements.txt b/requirements.txt
index e5398925..570bbfbb 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -5,7 +5,7 @@
 pbr!=2.1.0,>=2.0.0 # Apache-2.0
 
 enum34;python_version=='2.7' or python_version=='2.6' or python_version=='3.3' # BSD
-eventlet!=0.18.3,>=0.18.2 # MIT
+eventlet!=0.18.3,<0.21.0,>=0.18.2 # MIT
 netaddr!=0.7.16,>=0.7.13 # BSD
 tenacity>=3.2.1 # Apache-2.0
 six>=1.9.0 # MIT