diff --git a/include/mbedtls/config.h b/include/mbedtls/config.h
index b0296eb..109f217 100644
--- a/include/mbedtls/config.h
+++ b/include/mbedtls/config.h
@@ -128,7 +128,12 @@
  * MBEDTLS_PLATFORM_TIME_MACRO, MBEDTLS_PLATFORM_TIME_TYPE_MACRO and
  * MBEDTLS_PLATFORM_STD_TIME.
  *
- * Comment if your system does not support time functions
+ * Comment if your system does not support time functions.
+ *
+ * \note If MBEDTLS_TIMING_C is set - to enable the semi-portable timing
+ *       interface - timing.c will include time.h on suitable platforms
+ *       regardless of the setting of MBEDTLS_HAVE_TIME, unless
+ *       MBEDTLS_TIMING_ALT is used. See timing.c for more information.
  */
 #define MBEDTLS_HAVE_TIME
 
@@ -3466,6 +3471,10 @@
  * your own implementation of the whole module by setting
  * \c MBEDTLS_TIMING_ALT in the current file.
  *
+ * \note The timing module will include time.h on suitable platforms
+ *       regardless of the setting of MBEDTLS_HAVE_TIME, unless
+ *       MBEDTLS_TIMING_ALT is used. See timing.c for more information.
+ *
  * \note See also our Knowledge Base article about porting to a new
  * environment:
  * https://tls.mbed.org/kb/how-to/how-do-i-port-mbed-tls-to-a-new-environment-OS