diff --git a/include/mbedtls/md.h b/include/mbedtls/md.h
index 104c5777a..277656884 100644
--- a/include/mbedtls/md.h
+++ b/include/mbedtls/md.h
@@ -35,6 +35,11 @@
 #include MBEDTLS_CONFIG_FILE
 #endif
 
+#if ( defined(__ARMCC_VERSION) || defined(_MSC_VER) ) && \
+    !defined(inline) && !defined(__cplusplus)
+#define inline __inline
+#endif
+
 #define MBEDTLS_ERR_MD_FEATURE_UNAVAILABLE                -0x5080  /**< The selected feature is not available. */
 #define MBEDTLS_ERR_MD_BAD_INPUT_DATA                     -0x5100  /**< Bad input parameters to function. */
 #define MBEDTLS_ERR_MD_ALLOC_FAILED                       -0x5180  /**< Failed to allocate memory. */