diff --git a/ngraph/core/src/op/util/attr_types.cpp b/ngraph/core/src/op/util/attr_types.cpp
index 60af609c673269..3d109afeaf909e 100644
--- a/ngraph/core/src/op/util/attr_types.cpp
+++ b/ngraph/core/src/op/util/attr_types.cpp
@@ -13,6 +13,7 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 //*****************************************************************************
+#include <cctype>
 #include <map>
 
 #include "ngraph/attribute_visitor.hpp"