diff --git a/Modules/_zstd/compressor.c b/Modules/_zstd/compressor.c
index 0fc3d7d36c6..8ff2a3aadc1 100644
--- a/Modules/_zstd/compressor.c
+++ b/Modules/_zstd/compressor.c
@@ -512,7 +512,7 @@ error:
     return NULL;
 }
 
-#ifdef Py_DEBUG
+#ifndef NDEBUG
 static inline int
 mt_continue_should_break(ZSTD_inBuffer *in, ZSTD_outBuffer *out)
 {