diff --git a/CMakeLists.txt b/CMakeLists.txt
index b7b9d665d..ab9f634f7 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -24,7 +24,9 @@ endif()
 # Compiler flags
 set(CMAKE_CXX_STANDARD 11)
 set(CMAKE_CXX_STANDARD_REQUIRED ON)
-set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} ${OpenMP_CXX_FLAGS}")
+if(OpenMP_CXX_FOUND OR OPENMP_FOUND)
+  set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} ${OpenMP_CXX_FLAGS}")
+endif()
 set(CMAKE_POSITION_INDEPENDENT_CODE ON)
 if(MSVC)
   # Multithreaded compilation