diff --git a/Doc/ext/extending.tex b/Doc/ext/extending.tex
index 2b7963e665a..0f38e96f10f 100644
--- a/Doc/ext/extending.tex
+++ b/Doc/ext/extending.tex
@@ -1344,7 +1344,7 @@ import_spam(void)
 }
 #endif
 
-#endif /* !defined(Py_SPAMMODULE_H */
+#endif /* !defined(Py_SPAMMODULE_H) */
 \end{verbatim}
 
 All that a client module must do in order to have access to the