diff --git a/builtin/merge.c b/builtin/merge.c
index 23170f2d2a..b43876f68e 100644
--- a/builtin/merge.c
+++ b/builtin/merge.c
@@ -1599,6 +1599,21 @@ int cmd_merge(int argc, const char **argv, const char *prefix)
 		 */
 		refresh_cache(REFRESH_QUIET);
 		if (allow_trivial && fast_forward != FF_ONLY) {
+			/*
+			 * Must first ensure that index matches HEAD before
+			 * attempting a trivial merge.
+			 */
+			struct tree *head_tree = get_commit_tree(head_commit);
+			struct strbuf sb = STRBUF_INIT;
+
+			if (repo_index_has_changes(the_repository, head_tree,
+						   &sb)) {
+				error(_("Your local changes to the following files would be overwritten by merge:\n  %s"),
+				      sb.buf);
+				strbuf_release(&sb);
+				return 2;
+			}
+
 			/* See if it is really trivial. */
 			git_committer_info(IDENT_STRICT);
 			printf(_("Trying really trivial in-index merge...\n"));
diff --git a/t/t6424-merge-unrelated-index-changes.sh b/t/t6424-merge-unrelated-index-changes.sh
index eabe6bda83..187c761ad8 100755
--- a/t/t6424-merge-unrelated-index-changes.sh
+++ b/t/t6424-merge-unrelated-index-changes.sh
@@ -114,6 +114,19 @@ test_expect_success 'resolve, non-trivial' '
 	test_path_is_missing .git/MERGE_HEAD
 '
 
+test_expect_success 'resolve, trivial, related file removed' '
+	git reset --hard &&
+	git checkout B^0 &&
+
+	git rm a &&
+	test_path_is_missing a &&
+
+	test_must_fail git merge -s resolve C^0 &&
+
+	test_path_is_missing a &&
+	test_path_is_missing .git/MERGE_HEAD
+'
+
 test_expect_success 'resolve, non-trivial, related file removed' '
 	git reset --hard &&
 	git checkout B^0 &&
@@ -121,7 +134,14 @@ test_expect_success 'resolve, non-trivial, related file removed' '
 	git rm a &&
 	test_path_is_missing a &&
 
-	test_must_fail git merge -s resolve D^0 &&
+	# We also ask for recursive in order to turn off the "allow_trivial"
+	# setting in builtin/merge.c, and ensure that resolve really does
+	# correctly fail the merge (I guess this also tests that recursive
+	# correctly fails the merge, but the main thing we are attempting
+	# to test here is resolve and are just using the side effect of
+	# adding recursive to ensure that resolve is actually tested rather
+	# than the trivial merge codepath)
+	test_must_fail git merge -s resolve -s recursive D^0 &&
 
 	test_path_is_missing a &&
 	test_path_is_missing .git/MERGE_HEAD