diff --git a/ChangeLog b/ChangeLog
index fbc9d7bf6..e2389d57e 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -65,6 +65,8 @@ Bugfix
      returning. Fixes #2431.
    * Fix typo in net_would_block(). Fixes #528 reported by github-monoculture.
    * Remove redundant include file in timing.c. Fixes #2640 reported by irwir.
+   * Fix build failure when building with mingw on Windows by including
+     stdarg.h where needed. Fixes #2656.
 
 API Changes
    * Extend the MBEDTLS_SSL_EXPORT_KEYS to export the handshake randbytes,
diff --git a/include/mbedtls/platform.h b/include/mbedtls/platform.h
index 801a948bc..363d6b3db 100644
--- a/include/mbedtls/platform.h
+++ b/include/mbedtls/platform.h
@@ -256,6 +256,7 @@ int mbedtls_platform_set_snprintf( int (*snprintf_func)( char * s, size_t n,
  *   the destination buffer is too short.
  */
 #if defined(MBEDTLS_PLATFORM_HAS_NON_CONFORMING_VSNPRINTF)
+#include <stdarg.h>
 /* For Older Windows (inc. MSYS2), we provide our own fixed implementation */
 int mbedtls_platform_win32_vsnprintf( char *s, size_t n, const char *fmt, va_list arg );
 #endif