diff --git a/runtime/well_known_classes.cc b/runtime/well_known_classes.cc
index 4a3c3ec..fc3c879 100644
--- a/runtime/well_known_classes.cc
+++ b/runtime/well_known_classes.cc
@@ -18,6 +18,8 @@
 
 #include <stdlib.h>
 
+#include <sstream>
+
 #include "base/logging.h"
 #include "mirror/class.h"
 #include "ScopedLocalRef.h"