diff --git a/branch.c b/branch.c
index bde705b092b3c6..fc927b804a0524 100644
--- a/branch.c
+++ b/branch.c
@@ -10,6 +10,7 @@
 #include "worktree.h"
 #include "submodule-config.h"
 #include "run-command.h"
+#include "strmap.h"
 
 struct tracking {
 	struct refspec_item spec;
@@ -346,6 +347,41 @@ int validate_branchname(const char *name, struct strbuf *ref)
 	return ref_exists(ref->buf);
 }
 
+static int initialized_checked_out_branches;
+static struct strmap current_checked_out_branches = STRMAP_INIT;
+
+static void prepare_checked_out_branches(void)
+{
+	int i = 0;
+	struct worktree **worktrees;
+
+	if (initialized_checked_out_branches)
+		return;
+	initialized_checked_out_branches = 1;
+
+	worktrees = get_worktrees();
+
+	while (worktrees[i]) {
+		struct worktree *wt = worktrees[i++];
+
+		if (wt->is_bare)
+			continue;
+
+		if (wt->head_ref)
+			strmap_put(&current_checked_out_branches,
+				   wt->head_ref,
+				   xstrdup(wt->path));
+	}
+
+	free_worktrees(worktrees);
+}
+
+const char *branch_checked_out(const char *refname)
+{
+	prepare_checked_out_branches();
+	return strmap_get(&current_checked_out_branches, refname);
+}
+
 /*
  * Check if a branch 'name' can be created as a new branch; die otherwise.
  * 'force' can be used when it is OK for the named branch already exists.
diff --git a/branch.h b/branch.h
index 04df2aa5b515e9..60b25911f0ecd7 100644
--- a/branch.h
+++ b/branch.h
@@ -100,6 +100,13 @@ void create_branches_recursively(struct repository *r, const char *name,
 				 const char *tracking_name, int force,
 				 int reflog, int quiet, enum branch_track track,
 				 int dry_run);
+
+/*
+ * If the branch at 'refname' is currently checked out in a worktree,
+ * then return the path to that worktree.
+ */
+const char *branch_checked_out(const char *refname);
+
 /*
  * Check if 'name' can be a valid name for a branch; die otherwise.
  * Return 1 if the named branch already exists; return 0 otherwise.
diff --git a/t/t2407-worktree-heads.sh b/t/t2407-worktree-heads.sh
new file mode 100755
index 00000000000000..305ab46e38e24c
--- /dev/null
+++ b/t/t2407-worktree-heads.sh
@@ -0,0 +1,29 @@
+#!/bin/sh
+
+test_description='test operations trying to overwrite refs at worktree HEAD'
+
+TEST_PASSES_SANITIZE_LEAK=true
+. ./test-lib.sh
+
+test_expect_success 'setup' '
+	test_commit init &&
+	git branch -f fake-1 &&
+	git branch -f fake-2 &&
+
+	for i in 1 2 3 4
+	do
+		test_commit $i &&
+		git branch wt-$i &&
+		git worktree add wt-$i wt-$i || return 1
+	done
+'
+
+test_expect_success 'refuse to overwrite: checked out in worktree' '
+	for i in 1 2 3 4
+	do
+		test_must_fail git branch -f wt-$i HEAD 2>err
+		grep "cannot force update the branch" err || return 1
+	done
+'
+
+test_done