diff --git a/cpp/open3d/visualization/gui/Font.h b/cpp/open3d/visualization/gui/Font.h
index ba6f7d38df6..62467154ac7 100644
--- a/cpp/open3d/visualization/gui/Font.h
+++ b/cpp/open3d/visualization/gui/Font.h
@@ -7,6 +7,7 @@
 
 #pragma once
 
+#include <cstdint>
 #include <string>
 #include <vector>
 
diff --git a/cpp/open3d/visualization/gui/Util.h b/cpp/open3d/visualization/gui/Util.h
index a1fce75796f..375933bd6dd 100644
--- a/cpp/open3d/visualization/gui/Util.h
+++ b/cpp/open3d/visualization/gui/Util.h
@@ -10,6 +10,7 @@
 
 #include <imgui.h>
 
+#include <cstdint>
 #include <string>
 #include <vector>