diff --git a/ChangeLog b/ChangeLog
index 273d4bc9f..8667c9eee 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -2,6 +2,10 @@ mbed TLS ChangeLog (Sorted per branch, date)
 
 = mbed TLS 2.18.1 branch released 2019-07-12
 
+Bugfix
+   * Fix build failure when building with mingw on Windows by including
+     stdarg.h where needed. Fixes #2656.
+
 Changes
    * Enable building of Mbed TLS as a CMake subproject. Suggested and fixed by
      Ashley Duncan in #2609.
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