diff --git a/builtin-mv.c b/builtin-mv.c
index 593ff9e434..42c2e39b21 100644
--- a/builtin-mv.c
+++ b/builtin-mv.c
@@ -42,6 +42,18 @@ static void show_list(const char *label, struct path_list *list)
 	}
 }
 
+static const char *add_slash(const char *path)
+{
+	int len = strlen(path);
+	if (path[len - 1] != '/') {
+		char *with_slash = xmalloc(len + 2);
+		memcpy(with_slash, path, len);
+		strcat(with_slash + len, "/");
+		return with_slash;
+	}
+	return path;
+}
+
 static struct lock_file lock_file;
 
 int cmd_mv(int argc, const char **argv, char **envp)
@@ -50,6 +62,7 @@ int cmd_mv(int argc, const char **argv, char **envp)
 	int verbose = 0, show_only = 0, force = 0, ignore_errors = 0;
 	const char *prefix = setup_git_directory();
 	const char **source, **destination, **dest_path;
+	enum update_mode { BOTH = 0, WORKING_DIRECTORY, INDEX } *modes;
 	struct stat st;
 	struct path_list overwritten = {NULL, 0, 0, 0};
 	struct path_list src_for_dst = {NULL, 0, 0, 0};
@@ -94,11 +107,14 @@ int cmd_mv(int argc, const char **argv, char **envp)
 		usage(builtin_mv_usage);
 
 	source = copy_pathspec(prefix, argv + i, count, 0);
+	modes = xcalloc(count, sizeof(enum update_mode));
 	dest_path = copy_pathspec(prefix, argv + argc - 1, 1, 0);
 
-	if (!lstat(dest_path[0], &st) && S_ISDIR(st.st_mode))
+	if (!lstat(dest_path[0], &st) &&
+			S_ISDIR(st.st_mode)) {
+		dest_path[0] = add_slash(dest_path[0]);
 		destination = copy_pathspec(dest_path[0], argv + i, count, 1);
-	else {
+	} else {
 		if (count != 1)
 			usage(builtin_mv_usage);
 		destination = dest_path;
@@ -114,7 +130,64 @@ int cmd_mv(int argc, const char **argv, char **envp)
 
 		if (lstat(source[i], &st) < 0)
 			bad = "bad source";
-		else if (lstat(destination[i], &st) == 0) {
+
+		if (S_ISDIR(st.st_mode)) {
+			const char *dir = source[i], *dest_dir = destination[i];
+			int first, last, len = strlen(dir);
+
+			if (lstat(dest_dir, &st) == 0) {
+				bad = "cannot move directory over file";
+				goto next;
+			}
+
+			modes[i] = WORKING_DIRECTORY;
+
+			first = cache_name_pos(source[i], len);
+			if (first >= 0)
+				die ("Huh? %s/ is in index?", dir);
+
+			first = -1 - first;
+			for (last = first; last < active_nr; last++) {
+				const char *path = active_cache[last]->name;
+				if (strncmp(path, dir, len) || path[len] != '/')
+					break;
+			}
+
+			if (last - first < 1)
+				bad = "source directory is empty";
+			else if (!bad) {
+				int j, dst_len = strlen(dest_dir);
+
+				if (last - first > 0) {
+					source = realloc(source,
+							(count + last - first)
+							* sizeof(char *));
+					destination = realloc(destination,
+							(count + last - first)
+							* sizeof(char *));
+					modes = realloc(modes,
+							(count + last - first)
+							* sizeof(enum update_mode));
+				}
+
+				dest_dir = add_slash(dest_dir);
+
+				for (j = 0; j < last - first; j++) {
+					const char *path =
+						active_cache[first + j]->name;
+					source[count + j] = path;
+					destination[count + j] =
+						prefix_path(dest_dir, dst_len,
+							path + len);
+					modes[count + j] = INDEX;
+				}
+				count += last - first;
+			}
+
+			goto next;
+		}
+
+		if (!bad && lstat(destination[i], &st) == 0) {
 			bad = "destination exists";
 			if (force) {
 				/*
@@ -147,6 +220,7 @@ int cmd_mv(int argc, const char **argv, char **envp)
 				path_list_insert(destination[i], &src_for_dst);
 		}
 
+next:
 		if (bad) {
 			if (ignore_errors) {
 				if (--count > 0) {
@@ -157,7 +231,7 @@ int cmd_mv(int argc, const char **argv, char **envp)
 						(count - i) * sizeof(char *));
 				}
 			} else
-				die ("Error: %s, source=%s, destination=%s",
+				die ("%s, source=%s, destination=%s",
 				     bad, source[i], destination[i]);
 		}
 	}
@@ -166,12 +240,15 @@ int cmd_mv(int argc, const char **argv, char **envp)
 		if (show_only || verbose)
 			printf("Renaming %s to %s\n",
 			       source[i], destination[i]);
-		if (!show_only &&
+		if (!show_only && modes[i] != INDEX &&
 		    rename(source[i], destination[i]) < 0 &&
 		    !ignore_errors)
 			die ("renaming %s failed: %s",
 			     source[i], strerror(errno));
 
+		if (modes[i] == WORKING_DIRECTORY)
+			continue;
+
 		if (cache_name_pos(source[i], strlen(source[i])) >= 0) {
 			path_list_insert(source[i], &deleted);
 
diff --git a/t/t7001-mv.sh b/t/t7001-mv.sh
index 322eaadc73..900ca93cde 100755
--- a/t/t7001-mv.sh
+++ b/t/t7001-mv.sh
@@ -74,4 +74,8 @@ test_expect_success \
      git-diff-tree -r -M --name-status  HEAD^ HEAD | \
      grep -E "^R100.+path2/README.+path1/path2/README"'
 
+test_expect_failure \
+    'do not move directory over existing directory' \
+    'mkdir path0 && mkdir path0/path2 && git-mv path2 path0'
+
 test_done