diff --git a/compiler/optimizing/graph_visualizer.h b/compiler/optimizing/graph_visualizer.h
index 05984a0..4d8bec2 100644
--- a/compiler/optimizing/graph_visualizer.h
+++ b/compiler/optimizing/graph_visualizer.h
@@ -17,6 +17,8 @@
 #ifndef ART_COMPILER_OPTIMIZING_GRAPH_VISUALIZER_H_
 #define ART_COMPILER_OPTIMIZING_GRAPH_VISUALIZER_H_
 
+#include <ostream>
+
 #include "base/value_object.h"
 
 namespace art {