diff --git a/aegisub/src/ass_export_filter.cpp b/aegisub/src/ass_export_filter.cpp
index 258018a5f..609d12cf5 100644
--- a/aegisub/src/ass_export_filter.cpp
+++ b/aegisub/src/ass_export_filter.cpp
@@ -36,6 +36,10 @@
 
 #include "config.h"
 
+#ifndef AGI_PRE
+#include <algorithm>
+#endif
+
 #include "ass_export_filter.h"
 #include "ass_file.h"