diff --git a/drupal-code-quality/assets/.prettierignore b/drupal-code-quality/assets/.prettierignore
index 70d539b..942f0dc 100644
--- a/drupal-code-quality/assets/.prettierignore
+++ b/drupal-code-quality/assets/.prettierignore
@@ -2,3 +2,6 @@
 # Default ignore list used by Drupal GitLab CI templates (include.drupalci.main.yml).
 # CI creates this file when missing; we vendor it here to keep local runs in parity.
 *.yml
+# Drupal .inc files are PHP, but prettier parses as HTML by default.
+# PHP files should be checked by phpcs/phpcbf instead.
+*.inc