diff --git a/requirements-dev.txt b/requirements-dev.txt
index 9911431..432466d 100644
--- a/requirements-dev.txt
+++ b/requirements-dev.txt
@@ -5,7 +5,7 @@ more-itertools==5.0.0
 pluggy==0.8.0
 py==1.7.0
 pytest==4.0.2
-six==1.12.0
+six==1.13.0
 
 # Flake8
 flake8==3.6.0