diff --git a/requirements_dev.txt b/requirements_dev.txt
index 634bc1de7..c8fde0667 100644
--- a/requirements_dev.txt
+++ b/requirements_dev.txt
@@ -8,7 +8,7 @@ bumpversion==0.5.3
 # glotaran setup dependencies
 numpy==1.15.4
 scipy==1.2.0
-Cython==0.29.2
+Cython==0.29.6
 setuptools==40.6.3
 
 # documentation dependencies