diff --git a/requirements.txt b/requirements.txt
index e83a2e8..28ed2d3 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -7,5 +7,5 @@ coverage
 flake8
 Sphinx==1.5.2
 
-PyYAML==3.11
+PyYAML==5.1
 graphene>=2.0.dev