diff --git a/lib/compress/zstd_compress.c b/lib/compress/zstd_compress.c
index b1bb9fa10..434c23000 100644
--- a/lib/compress/zstd_compress.c
+++ b/lib/compress/zstd_compress.c
@@ -1542,6 +1542,12 @@ static size_t ZSTD_resetCCtx_internal(ZSTD_CCtx* zc,
 
     zc->isFirstBlock = 1;
 
+    if (params.cParams.strategy >= ZSTD_btopt && params.cParams.windowLog >= 27) {
+        /* Enable LDM by default for optimal parser and window size >= 128MB */
+        DEBUGLOG(4, "LDM enabled by default (window size >= 128MB, strategy >= btopt)");
+        params.ldmParams.enableLdm = 1;
+    }
+
     if (params.ldmParams.enableLdm) {
         /* Adjust long distance matching parameters */
         ZSTD_ldm_adjustParameters(&params.ldmParams, &params.cParams);