diff --git a/net/http/test/client_tls_test.cpp b/net/http/test/client_tls_test.cpp
index 533489b9..5868ecd1 100644
--- a/net/http/test/client_tls_test.cpp
+++ b/net/http/test/client_tls_test.cpp
@@ -14,6 +14,7 @@ See the License for the specific language governing permissions and
 limitations under the License.
 */
 
+#include <openssl/ssl.h>
 #include <gtest/gtest.h>
 
 #include <photon/photon.h>