diff --git a/{{cookiecutter.project_slug}}/.yamllint.yml b/{{cookiecutter.project_slug}}/.yamllint.yml
index 536f9c6..cf68c8e 100644
--- a/{{cookiecutter.project_slug}}/.yamllint.yml
+++ b/{{cookiecutter.project_slug}}/.yamllint.yml
@@ -38,6 +38,8 @@ rules:
     level: error
   new-lines:
     type: unix
+  octal-values:
+    forbid-implicit-octal: true
   trailing-spaces:
     level: error
   truthy: disable