diff --git a/aegisub/src/charset_detect.cpp b/aegisub/src/charset_detect.cpp
index 6def21b97..42bb4c7f7 100644
--- a/aegisub/src/charset_detect.cpp
+++ b/aegisub/src/charset_detect.cpp
@@ -41,6 +41,7 @@
 
 #ifdef WITH_UNIVCHARDET
 #ifndef AGI_PRE
+#include <fstream>
 #include <list>
 
 #include <wx/choicdlg.h>