diff --git a/main.go b/main.go
index c604962..f1a0995 100644
--- a/main.go
+++ b/main.go
@@ -309,6 +309,7 @@ func licenseHeader(path string, tmpl *template.Template, data licenseData) ([]by
 		".groovy",
 		".hcl",
 		".m", ".mm",
+		".p4",
 		".php",
 		".proto",
 		".rs",