diff --git a/include/Lv2UridMap.h b/include/Lv2UridMap.h
index f1ddb6253..39cfcc44f 100644
--- a/include/Lv2UridMap.h
+++ b/include/Lv2UridMap.h
@@ -31,6 +31,7 @@
 
 #include <lv2/lv2plug.in/ns/ext/urid/urid.h>
 #include <mutex> // TODO: use semaphore, even though this is not realtime critical
+#include <string>
 #include <unordered_map>
 #include <vector>