diff --git a/setup.py b/setup.py
index 3315f76..e78d576 100644
--- a/setup.py
+++ b/setup.py
@@ -46,7 +46,7 @@ def run(self):
     },
 
     # Package dependencies.
-    install_requires = ['pyyaml==3.12'],
+    install_requires = ['pyyaml==5.4'],
     extras_require = {
         'test': ['pytest', 'pytest-cov'],
     },