diff --git a/aegisub/docs/doxygen/doxyfile b/aegisub/docs/doxygen/doxyfile
index 46a68fe23..2eb78503b 100644
--- a/aegisub/docs/doxygen/doxyfile
+++ b/aegisub/docs/doxygen/doxyfile
@@ -125,7 +125,7 @@ IGNORE_PREFIX          =
 #---------------------------------------------------------------------------
 GENERATE_HTML          = YES
 HTML_OUTPUT            = ./
-HTML_FILE_EXTENSION    = html
+HTML_FILE_EXTENSION    = .html
 HTML_HEADER            = html_header.html
 HTML_FOOTER            = 
 HTML_STYLESHEET        =