diff --git a/src/CalcManager/ExpressionCommandInterface.h b/src/CalcManager/ExpressionCommandInterface.h
index ce89dd81..94bae836 100644
--- a/src/CalcManager/ExpressionCommandInterface.h
+++ b/src/CalcManager/ExpressionCommandInterface.h
@@ -1,7 +1,9 @@
-// Copyright (c) Microsoft Corporation. All rights reserved.
+// Copyright (c) Microsoft Corporation. All rights reserved.
 // Licensed under the MIT License.
 
 #pragma once
+
+#include <memory> // for std::shared_ptr
 #include "CalculatorVector.h"
 #include "Command.h"