diff --git a/src/help_gui.cpp b/src/help_gui.cpp
index c78c985fb7..6ee6d73c00 100644
--- a/src/help_gui.cpp
+++ b/src/help_gui.cpp
@@ -21,6 +21,8 @@
 #include "widgets/help_widget.h"
 #include "widgets/misc_widget.h"
 
+#include <unordered_map>
+
 #include "safeguards.h"
 
 static const std::string README_FILENAME = "README.md";