diff --git a/ortools/gscip/gscip.h b/ortools/gscip/gscip.h
index 0bf6684ade..e96a0fbd4a 100644
--- a/ortools/gscip/gscip.h
+++ b/ortools/gscip/gscip.h
@@ -57,6 +57,7 @@
 #ifndef OR_TOOLS_GSCIP_GSCIP_H_
 #define OR_TOOLS_GSCIP_GSCIP_H_
 
+#include <atomic>
 #include <cstdint>
 #include <functional>
 #include <limits>
diff --git a/ortools/linear_solver/solve_mp_model.h b/ortools/linear_solver/solve_mp_model.h
index 59a4dc0b04..528d39b9de 100644
--- a/ortools/linear_solver/solve_mp_model.h
+++ b/ortools/linear_solver/solve_mp_model.h
@@ -19,6 +19,7 @@
 #define OR_TOOLS_LINEAR_SOLVER_SOLVE_MP_MODEL_H_
 
 #include <atomic>
+#include <string>
 
 #include "ortools/linear_solver/linear_solver.pb.h"