diff --git a/runtime/doc/ui.txt b/runtime/doc/ui.txt
index 8546478935..c81420d1f2 100644
--- a/runtime/doc/ui.txt
+++ b/runtime/doc/ui.txt
@@ -228,6 +228,10 @@ the editor.
 	however a UI might still use such options when rendering raw text
 	sent from Nvim, like for |ui-cmdline|.
 
+["chdir", path] ~
+	The |current-directory| of the embedded Nvim process changed to
+	`path`.
+
 ["mode_change", mode, mode_idx] ~
 	Editor mode changed.  The `mode` parameter is a string representing
 	the current mode. `mode_idx` is an index into the array emitted in
diff --git a/src/nvim/api/ui_events.in.h b/src/nvim/api/ui_events.in.h
index bda0c72423..c2f02c34f8 100644
--- a/src/nvim/api/ui_events.in.h
+++ b/src/nvim/api/ui_events.in.h
@@ -39,6 +39,8 @@ void screenshot(String path)
   FUNC_API_SINCE(7);
 void option_set(String name, Object value)
   FUNC_API_SINCE(4);
+void chdir(String path)
+  FUNC_API_SINCE(12);
 // Stop event is not exported as such, represented by EOF in the msgpack stream.
 void stop(void)
   FUNC_API_NOEXPORT;
diff --git a/src/nvim/os/fs.c b/src/nvim/os/fs.c
index 09203990bb..d80539708d 100644
--- a/src/nvim/os/fs.c
+++ b/src/nvim/os/fs.c
@@ -33,6 +33,7 @@
 # include <sys/xattr.h>
 #endif
 
+#include "nvim/api/private/helpers.h"
 #include "nvim/ascii_defs.h"
 #include "nvim/gettext_defs.h"
 #include "nvim/globals.h"
@@ -44,6 +45,7 @@
 #include "nvim/os/os.h"
 #include "nvim/path.h"
 #include "nvim/types_defs.h"
+#include "nvim/ui.h"
 #include "nvim/vim_defs.h"
 
 #ifdef HAVE_SYS_UIO_H
@@ -90,7 +92,11 @@ int os_chdir(const char *path)
     smsg(0, "chdir(%s)", path);
     verbose_leave();
   }
-  return uv_chdir(path);
+  int err = uv_chdir(path);
+  if (err == 0) {
+    ui_call_chdir(cstr_as_string((char *)path));
+  }
+  return err;
 }
 
 /// Get the name of current directory.
diff --git a/src/nvim/tui/tui.c b/src/nvim/tui/tui.c
index 6b8b73a2a0..f9560ce076 100644
--- a/src/nvim/tui/tui.c
+++ b/src/nvim/tui/tui.c
@@ -1500,6 +1500,14 @@ void tui_option_set(TUIData *tui, String name, Object value)
   }
 }
 
+void tui_chdir(TUIData *tui, String path)
+{
+  int err = uv_chdir(path.data);
+  if (err != 0) {
+    ELOG("Failed to chdir to %s: %s", path.data, strerror(err));
+  }
+}
+
 void tui_raw_line(TUIData *tui, Integer g, Integer linerow, Integer startcol, Integer endcol,
                   Integer clearcol, Integer clearattr, LineFlags flags, const schar_T *chunk,
                   const sattr_T *attrs)
diff --git a/src/nvim/ui.c b/src/nvim/ui.c
index 8888535878..316342c028 100644
--- a/src/nvim/ui.c
+++ b/src/nvim/ui.c
@@ -384,6 +384,12 @@ void ui_attach_impl(UI *ui, uint64_t chanid)
   ui_refresh_options();
   resettitle();
 
+  char cwd[MAXPATHL];
+  size_t cwdlen = sizeof(cwd);
+  if (uv_cwd(cwd, &cwdlen) == 0) {
+    ui_call_chdir((String){ .data = cwd, .size = cwdlen });
+  }
+
   for (UIExtension i = kUIGlobalCount; (int)i < kUIExtCount; i++) {
     ui_set_ext_option(ui, i, ui->ui_ext[i]);
   }
diff --git a/test/functional/ui/embed_spec.lua b/test/functional/ui/embed_spec.lua
index e655ee1b54..f6bdd2215d 100644
--- a/test/functional/ui/embed_spec.lua
+++ b/test/functional/ui/embed_spec.lua
@@ -171,6 +171,56 @@ describe('--embed UI', function()
     }
     eq({ [16711935] = true }, seen) -- we only saw the last one, despite 16777215 was set internally earlier
   end)
+
+  it('updates cwd of attached UI #21771', function()
+    clear { args_rm = { '--headless' } }
+
+    local screen = Screen.new(40, 8)
+    screen:attach()
+
+    screen:expect {
+      condition = function()
+        eq(helpers.paths.test_source_path, screen.pwd)
+      end,
+    }
+
+    -- Change global cwd
+    helpers.command(string.format('cd %s/src/nvim', helpers.paths.test_source_path))
+
+    screen:expect {
+      condition = function()
+        eq(string.format('%s/src/nvim', helpers.paths.test_source_path), screen.pwd)
+      end,
+    }
+
+    -- Split the window and change the cwd in the split
+    helpers.command('new')
+    helpers.command(string.format('lcd %s/test', helpers.paths.test_source_path))
+
+    screen:expect {
+      condition = function()
+        eq(string.format('%s/test', helpers.paths.test_source_path), screen.pwd)
+      end,
+    }
+
+    -- Move to the original window
+    helpers.command('wincmd p')
+
+    screen:expect {
+      condition = function()
+        eq(string.format('%s/src/nvim', helpers.paths.test_source_path), screen.pwd)
+      end,
+    }
+
+    -- Change global cwd again
+    helpers.command(string.format('cd %s', helpers.paths.test_source_path))
+
+    screen:expect {
+      condition = function()
+        eq(helpers.paths.test_source_path, screen.pwd)
+      end,
+    }
+  end)
 end)
 
 describe('--embed --listen UI', function()
diff --git a/test/functional/ui/screen.lua b/test/functional/ui/screen.lua
index 644ee910b6..07333f2e21 100644
--- a/test/functional/ui/screen.lua
+++ b/test/functional/ui/screen.lua
@@ -140,6 +140,7 @@ function Screen.new(width, height)
     suspended = false,
     mode = 'normal',
     options = {},
+    pwd = '',
     popupmenu = nil,
     cmdline = {},
     cmdline_block = {},
@@ -212,7 +213,6 @@ function Screen:attach(options, session)
   if options.ext_linegrid == nil then
     options.ext_linegrid = true
   end
-
   self._session = session
   self._options = options
   self._clear_attrs = (not options.ext_linegrid) and {} or nil
@@ -1108,6 +1108,10 @@ function Screen:_handle_option_set(name, value)
   self.options[name] = value
 end
 
+function Screen:_handle_chdir(path)
+  self.pwd = vim.fs.normalize(path, { expand_env = false })
+end
+
 function Screen:_handle_popupmenu_show(items, selected, row, col, grid)
   self.popupmenu = { items = items, pos = selected, anchor = { grid, row, col } }
 end