diff --git a/imperative/src/include/megbrain/imperative/backward_graph_opt.h b/imperative/src/include/megbrain/imperative/backward_graph_opt.h
index 02dfe044..357b80d8 100644
--- a/imperative/src/include/megbrain/imperative/backward_graph_opt.h
+++ b/imperative/src/include/megbrain/imperative/backward_graph_opt.h
@@ -9,6 +9,8 @@
  * "AS IS" BASIS, WITHOUT ARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  */
 
+#pragma once
+
 #include "./op_def.h"
 
 namespace mgb::imperative {
diff --git a/imperative/src/include/megbrain/imperative/interpreter.h b/imperative/src/include/megbrain/imperative/interpreter.h
index 86fe691a..bd440524 100644
--- a/imperative/src/include/megbrain/imperative/interpreter.h
+++ b/imperative/src/include/megbrain/imperative/interpreter.h
@@ -9,6 +9,8 @@
  * "AS IS" BASIS, WITHOUT ARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  */
 
+#pragma once
+
 #include <any>
 #include <atomic>