diff --git a/include/in_mem_data_store.h b/include/in_mem_data_store.h
index d1ad795f6..0a0a617da 100644
--- a/include/in_mem_data_store.h
+++ b/include/in_mem_data_store.h
@@ -1,5 +1,6 @@
 // Copyright (c) Microsoft Corporation. All rights reserved.
 // Licensed under the MIT license.
+#pragma once
 
 #include <shared_mutex>
 #include <memory>
diff --git a/include/index_build_params.h b/include/index_build_params.h
index 0233fcec4..d4f454830 100644
--- a/include/index_build_params.h
+++ b/include/index_build_params.h
@@ -1,3 +1,5 @@
+#pragma once
+
 #include "common_includes.h"
 #include "parameters.h"
 
diff --git a/include/index_config.h b/include/index_config.h
index 452498b01..a8e64d08c 100644
--- a/include/index_config.h
+++ b/include/index_config.h
@@ -1,3 +1,5 @@
+#pragma once
+
 #include "common_includes.h"
 #include "parameters.h"
 
diff --git a/include/index_factory.h b/include/index_factory.h
index 80bc40dba..76fb0b978 100644
--- a/include/index_factory.h
+++ b/include/index_factory.h
@@ -1,3 +1,5 @@
+#pragma once
+
 #include "index.h"
 #include "abstract_graph_store.h"
 #include "in_mem_graph_store.h"
diff --git a/include/locking.h b/include/locking.h
index 2a70f4ffa..890c24a2b 100644
--- a/include/locking.h
+++ b/include/locking.h
@@ -1,5 +1,6 @@
 // Copyright (c) Microsoft Corporation. All rights reserved.
 // Licensed under the MIT license.
+#pragma once
 
 #include <mutex>
 
diff --git a/include/timer.h b/include/timer.h
index 5ddc3c857..325edf302 100644
--- a/include/timer.h
+++ b/include/timer.h
@@ -1,5 +1,6 @@
 // Copyright (c) Microsoft Corporation. All rights reserved.
 // Licensed under the MIT license.
+#pragma once
 
 #include <chrono>
 
diff --git a/include/windows_slim_lock.h b/include/windows_slim_lock.h
index 5d0d65508..7fc09b8f9 100644
--- a/include/windows_slim_lock.h
+++ b/include/windows_slim_lock.h
@@ -1,5 +1,6 @@
 // Copyright (c) Microsoft Corporation. All rights reserved.
 // Licensed under the MIT license.
+#pragma once
 
 #ifndef WIN32_LEAN_AND_MEAN
 #define WIN32_LEAN_AND_MEAN