diff --git a/builtin/commit.c b/builtin/commit.c
index 4cbd5ff..6163972 100644
--- a/builtin/commit.c
+++ b/builtin/commit.c
@@ -726,9 +726,18 @@
 				      &sb, &ctx);
 		hook_arg1 = "message";
 	} else if (!stat(git_path_merge_msg(), &statbuf)) {
+		/*
+		 * prepend SQUASH_MSG here if it exists and a
+		 * "merge --squash" was originally performed
+		 */
+		if (!stat(git_path_squash_msg(), &statbuf)) {
+			if (strbuf_read_file(&sb, git_path_squash_msg(), 0) < 0)
+				die_errno(_("could not read SQUASH_MSG"));
+			hook_arg1 = "squash";
+		} else
+			hook_arg1 = "merge";
 		if (strbuf_read_file(&sb, git_path_merge_msg(), 0) < 0)
 			die_errno(_("could not read MERGE_MSG"));
-		hook_arg1 = "merge";
 	} else if (!stat(git_path_squash_msg(), &statbuf)) {
 		if (strbuf_read_file(&sb, git_path_squash_msg(), 0) < 0)
 			die_errno(_("could not read SQUASH_MSG"));