diff --git a/Modules/_decimal/libmpdec/mpdecimal.c b/Modules/_decimal/libmpdec/mpdecimal.c
index ad8db508b36f0a5..28b639ccb405f68 100644
--- a/Modules/_decimal/libmpdec/mpdecimal.c
+++ b/Modules/_decimal/libmpdec/mpdecimal.c
@@ -64,7 +64,7 @@
 
 #if defined(_MSC_VER)
   #define ALWAYS_INLINE __forceinline
-#elif defined(LEGACY_COMPILER)
+#elif defined(__IBMC__) || defined(LEGACY_COMPILER)
   #define ALWAYS_INLINE
   #undef inline
   #define inline