diff --git a/iwyu_generate_mappings.awk b/iwyu_generate_mappings.awk
index b48578345a..199150a52b 100644
--- a/iwyu_generate_mappings.awk
+++ b/iwyu_generate_mappings.awk
@@ -17,7 +17,7 @@ BEGIN {
 /^(.*)\.generated\.h/ {
   body = $0
   header = body
-  sub(/\.generated\.h$/, ".h", header)
+  sub(/\.generated\.h$/, ".hpp", header)
   print "{ include: [\"\\\"" body "\\\"\", private, \"\\\"" header "\\\"\", public] },"
 }