diff --git a/aegisub/libaegisub/include/libaegisub/ass/dialogue_parser.h b/aegisub/libaegisub/include/libaegisub/ass/dialogue_parser.h
index 05ced523f..10ac62685 100644
--- a/aegisub/libaegisub/include/libaegisub/ass/dialogue_parser.h
+++ b/aegisub/libaegisub/include/libaegisub/ass/dialogue_parser.h
@@ -14,6 +14,7 @@
 //
 // Aegisub Project http://www.aegisub.org/
 
+#include <string>
 #include <vector>
 
 #undef ERROR