diff --git a/Documentation/git-worktree.txt b/Documentation/git-worktree.txt
index 27feff6dba..b49b25bf52 100644
--- a/Documentation/git-worktree.txt
+++ b/Documentation/git-worktree.txt
@@ -11,6 +11,7 @@ SYNOPSIS
 [verse]
 'git worktree add' [-f] [--detach] [--checkout] [-b <new-branch>] <path> [<branch>]
 'git worktree list' [--porcelain]
+'git worktree lock' [--reason <string>] <worktree>
 'git worktree prune' [-n] [-v] [--expire <expire>]
 
 DESCRIPTION
@@ -38,9 +39,8 @@ section "DETAILS" for more information.
 
 If a linked working tree is stored on a portable device or network share
 which is not always mounted, you can prevent its administrative files from
-being pruned by creating a file named 'locked' alongside the other
-administrative files, optionally containing a plain text reason that
-pruning should be suppressed. See section "DETAILS" for more information.
+being pruned by issuing the `git worktree lock` command, optionally
+specifying `--reason` to explain why the working tree is locked.
 
 COMMANDS
 --------
@@ -61,6 +61,14 @@ each of the linked worktrees.  The output details include if the worktree is
 bare, the revision currently checked out, and the branch currently checked out
 (or 'detached HEAD' if none).
 
+lock::
+
+If a working tree is on a portable device or network share which
+is not always mounted, lock it to prevent its administrative
+files from being pruned automatically. This also prevents it from
+being moved or deleted. Optionally, specify a reason for the lock
+with `--reason`.
+
 prune::
 
 Prune working tree information in $GIT_DIR/worktrees.
@@ -110,6 +118,13 @@ OPTIONS
 --expire <time>::
 	With `prune`, only expire unused working trees older than <time>.
 
+--reason <string>::
+	With `lock`, an explanation why the working tree is locked.
+
+<worktree>::
+	Working trees can be identified by path, either relative or
+	absolute.
+
 DETAILS
 -------
 Each linked working tree has a private sub-directory in the repository's
@@ -150,7 +165,8 @@ instead.
 
 To prevent a $GIT_DIR/worktrees entry from being pruned (which
 can be useful in some situations, such as when the
-entry's working tree is stored on a portable device), add a file named
+entry's working tree is stored on a portable device), use the
+`git worktree lock` command, which adds a file named
 'locked' to the entry's directory. The file contains the reason in
 plain text. For example, if a linked working tree's `.git` file points
 to `/path/main/.git/worktrees/test-next` then a file named
@@ -226,8 +242,6 @@ performed manually, such as:
 - `remove` to remove a linked working tree and its administrative files (and
   warn if the working tree is dirty)
 - `mv` to move or rename a working tree and update its administrative files
-- `lock` to prevent automatic pruning of administrative files (for instance,
-  for a working tree on a portable device)
 
 GIT
 ---
diff --git a/builtin/worktree.c b/builtin/worktree.c
index f9dac376f7..3b9220f7a6 100644
--- a/builtin/worktree.c
+++ b/builtin/worktree.c
@@ -14,6 +14,7 @@
 static const char * const worktree_usage[] = {
 	N_("git worktree add [<options>] <path> [<branch>]"),
 	N_("git worktree list [<options>]"),
+	N_("git worktree lock [<options>] <path>"),
 	N_("git worktree prune [<options>]"),
 	NULL
 };
@@ -459,6 +460,41 @@ static int list(int ac, const char **av, const char *prefix)
 	return 0;
 }
 
+static int lock_worktree(int ac, const char **av, const char *prefix)
+{
+	const char *reason = "", *old_reason;
+	struct option options[] = {
+		OPT_STRING(0, "reason", &reason, N_("string"),
+			   N_("reason for locking")),
+		OPT_END()
+	};
+	struct worktree **worktrees, *wt;
+
+	ac = parse_options(ac, av, prefix, options, worktree_usage, 0);
+	if (ac != 1)
+		usage_with_options(worktree_usage, options);
+
+	worktrees = get_worktrees();
+	wt = find_worktree(worktrees, prefix, av[0]);
+	if (!wt)
+		die(_("'%s' is not a working tree"), av[0]);
+	if (is_main_worktree(wt))
+		die(_("The main working tree cannot be locked or unlocked"));
+
+	old_reason = is_worktree_locked(wt);
+	if (old_reason) {
+		if (*old_reason)
+			die(_("'%s' is already locked, reason: %s"),
+			    av[0], old_reason);
+		die(_("'%s' is already locked"), av[0]);
+	}
+
+	write_file(git_common_path("worktrees/%s/locked", wt->id),
+		   "%s", reason);
+	free_worktrees(worktrees);
+	return 0;
+}
+
 int cmd_worktree(int ac, const char **av, const char *prefix)
 {
 	struct option options[] = {
@@ -475,5 +511,7 @@ int cmd_worktree(int ac, const char **av, const char *prefix)
 		return prune(ac - 1, av + 1, prefix);
 	if (!strcmp(av[1], "list"))
 		return list(ac - 1, av + 1, prefix);
+	if (!strcmp(av[1], "lock"))
+		return lock_worktree(ac - 1, av + 1, prefix);
 	usage_with_options(worktree_usage, options);
 }
diff --git a/contrib/completion/git-completion.bash b/contrib/completion/git-completion.bash
index 951a186df0..f88727dfe7 100644
--- a/contrib/completion/git-completion.bash
+++ b/contrib/completion/git-completion.bash
@@ -2597,7 +2597,7 @@ _git_whatchanged ()
 
 _git_worktree ()
 {
-	local subcommands="add list prune"
+	local subcommands="add list lock prune"
 	local subcommand="$(__git_find_on_cmdline "$subcommands")"
 	if [ -z "$subcommand" ]; then
 		__gitcomp "$subcommands"
@@ -2609,6 +2609,9 @@ _git_worktree ()
 		list,--*)
 			__gitcomp "--porcelain"
 			;;
+		lock,--*)
+			__gitcomp "--reason"
+			;;
 		prune,--*)
 			__gitcomp "--dry-run --expire --verbose"
 			;;
diff --git a/t/t2028-worktree-move.sh b/t/t2028-worktree-move.sh
new file mode 100755
index 0000000000..3a8512c030
--- /dev/null
+++ b/t/t2028-worktree-move.sh
@@ -0,0 +1,48 @@
+#!/bin/sh
+
+test_description='test git worktree move, remove, lock and unlock'
+
+. ./test-lib.sh
+
+test_expect_success 'setup' '
+	test_commit init &&
+	git worktree add source &&
+	git worktree list --porcelain | grep "^worktree" >actual &&
+	cat <<-EOF >expected &&
+	worktree $(pwd)
+	worktree $(pwd)/source
+	EOF
+	test_cmp expected actual
+'
+
+test_expect_success 'lock main worktree' '
+	test_must_fail git worktree lock .
+'
+
+test_expect_success 'lock linked worktree' '
+	git worktree lock --reason hahaha source &&
+	echo hahaha >expected &&
+	test_cmp expected .git/worktrees/source/locked
+'
+
+test_expect_success 'lock linked worktree from another worktree' '
+	rm .git/worktrees/source/locked &&
+	git worktree add elsewhere &&
+	git -C elsewhere worktree lock --reason hahaha ../source &&
+	echo hahaha >expected &&
+	test_cmp expected .git/worktrees/source/locked
+'
+
+test_expect_success 'lock worktree twice' '
+	test_must_fail git worktree lock source &&
+	echo hahaha >expected &&
+	test_cmp expected .git/worktrees/source/locked
+'
+
+test_expect_success 'lock worktree twice (from the locked worktree)' '
+	test_must_fail git -C source worktree lock . &&
+	echo hahaha >expected &&
+	test_cmp expected .git/worktrees/source/locked
+'
+
+test_done