diff --git a/.github/PULL_REQUEST_TEMPLATE.md b/.github/PULL_REQUEST_TEMPLATE.md
index 22b9edb3ccb..0a79fe9179e 100644
--- a/.github/PULL_REQUEST_TEMPLATE.md
+++ b/.github/PULL_REQUEST_TEMPLATE.md
@@ -16,6 +16,7 @@ Fixes #
 - [ ] Write detailed docstrings for all functions/methods.
 - [ ] If wrapping a new module, open a 'Wrap new GMT module' issue and submit reasonably-sized PRs.
 - [ ] If adding new functionality, add an example to docstrings or tutorials.
+- [ ] Use underscores (not hyphens) in names of Python files and directories.
 
 **Slash Commands**