diff --git a/mbed-client-mbedtls/m2mconnectionsecuritypimpl.h b/mbed-client-mbedtls/m2mconnectionsecuritypimpl.h
index 28235ba..bb13af4 100644
--- a/mbed-client-mbedtls/m2mconnectionsecuritypimpl.h
+++ b/mbed-client-mbedtls/m2mconnectionsecuritypimpl.h
@@ -23,6 +23,7 @@
 #include "mbed-client/m2msecurity.h"
 
 #include "mbedtls/config.h"
+#include "mbedtls/platform.h"
 #include "mbedtls/debug.h"
 #include "mbedtls/ssl.h"
 #include "mbedtls/entropy.h"