diff --git a/comtypes/server/register.py b/comtypes/server/register.py
index e0ea0dc2..1d17cd43 100644
--- a/comtypes/server/register.py
+++ b/comtypes/server/register.py
@@ -36,18 +36,24 @@
   python mycomobj.py /nodebug
 """
 
+import ctypes
 import logging
 import os
 import sys
 import winreg
-from ctypes import WinError, c_ulong, c_wchar_p, create_string_buffer, sizeof, windll
+from ctypes import WinError, windll
 from typing import Iterator, Tuple
 
 import comtypes
 import comtypes.server.inprocserver
 from comtypes.hresult import *
 from comtypes.server import w_getopt
-from comtypes.typeinfo import REGKIND_REGISTER, LoadTypeLibEx, UnRegisterTypeLib
+from comtypes.typeinfo import (
+    REGKIND_REGISTER,
+    GetModuleFileName,
+    LoadTypeLibEx,
+    UnRegisterTypeLib,
+)
 
 _debug = logging.getLogger(__name__).debug
 
@@ -67,7 +73,7 @@ def _non_zero(retval, func, args):
 
 SHDeleteKey = windll.shlwapi.SHDeleteKeyW
 SHDeleteKey.errcheck = _non_zero
-SHDeleteKey.argtypes = c_ulong, c_wchar_p
+SHDeleteKey.argtypes = ctypes.c_ulong, ctypes.c_wchar_p
 
 Set = set
 
@@ -219,9 +225,7 @@ def _get_serverdll():
     """Return the pathname of the dll hosting the COM object."""
     handle = getattr(sys, "frozendllhandle", None)
     if handle is not None:
-        buf = create_string_buffer(260)
-        windll.kernel32.GetModuleFileNameA(handle, buf, sizeof(buf))
-        return buf[:]
+        return GetModuleFileName(handle, 260)
     import _ctypes
 
     return _ctypes.__file__
diff --git a/comtypes/test/test_server_register.py b/comtypes/test/test_server_register.py
index 83fc78b2..e252dfae 100644
--- a/comtypes/test/test_server_register.py
+++ b/comtypes/test/test_server_register.py
@@ -1,5 +1,4 @@
 import _ctypes
-import ctypes
 import os
 import sys
 import unittest as ut
@@ -194,18 +193,16 @@ class Test_get_serverdll(ut.TestCase):
     def test_nonfrozen(self):
         self.assertEqual(_ctypes.__file__, _get_serverdll())
 
-    def test_frozen(self):
-        with mock.patch.object(register, "sys") as _sys:
-            with mock.patch.object(register, "windll") as _windll:
-                handle = 1234
-                _sys.frozendllhandle = handle
-                self.assertEqual(b"\x00" * 260, _get_serverdll())
-                GetModuleFileName = _windll.kernel32.GetModuleFileNameA
-                (((hModule, lpFilename, nSize), _),) = GetModuleFileName.call_args_list
-                self.assertEqual(handle, hModule)
-                buf_type = type(ctypes.create_string_buffer(260))
-                self.assertIsInstance(lpFilename, buf_type)
-                self.assertEqual(260, nSize)
+    @mock.patch.object(register, "GetModuleFileName")
+    @mock.patch.object(register, "sys")
+    def test_frozen(self, _sys, GetModuleFileName):
+        handle, dll_path = 1234, r"path\to\frozendll"
+        _sys.frozendllhandle = handle
+        GetModuleFileName.return_value = dll_path
+        self.assertEqual(r"path\to\frozendll", _get_serverdll())
+        (((hmodule, maxsize), _),) = GetModuleFileName.call_args_list
+        self.assertEqual(handle, hmodule)
+        self.assertEqual(260, maxsize)
 
 
 class Test_NonFrozen_RegistryEntries(ut.TestCase):
diff --git a/comtypes/test/test_typeinfo.py b/comtypes/test/test_typeinfo.py
index eaad4c73..1426e350 100644
--- a/comtypes/test/test_typeinfo.py
+++ b/comtypes/test/test_typeinfo.py
@@ -1,15 +1,15 @@
-import os
+import ctypes
+import sys
 import unittest
-from ctypes import POINTER, byref
+
 from comtypes import GUID, COMError
-from comtypes.automation import DISPATCH_METHOD
 from comtypes.typeinfo import (
-    LoadTypeLibEx,
+    TKIND_DISPATCH,
+    TKIND_INTERFACE,
+    GetModuleFileName,
     LoadRegTypeLib,
+    LoadTypeLibEx,
     QueryPathOfRegTypeLib,
-    TKIND_INTERFACE,
-    TKIND_DISPATCH,
-    TKIND_ENUM,
 )
 
 
@@ -94,5 +94,17 @@ def test_TypeInfo(self):
         self.assertEqual(guid, ti.GetTypeAttr().guid)
 
 
+class Test_GetModuleFileName(unittest.TestCase):
+    def test_null_handler(self):
+        self.assertEqual(GetModuleFileName(None, 260), sys.executable)
+
+    def test_loaded_module_handle(self):
+        import _ctypes
+
+        dll_path = _ctypes.__file__
+        hmodule = ctypes.WinDLL(dll_path)._handle
+        self.assertEqual(GetModuleFileName(hmodule, 260), dll_path)
+
+
 if __name__ == "__main__":
     unittest.main()
diff --git a/comtypes/typeinfo.py b/comtypes/typeinfo.py
index 077a492c..fb17000c 100644
--- a/comtypes/typeinfo.py
+++ b/comtypes/typeinfo.py
@@ -3,19 +3,48 @@
 # generated by 'xml2py'
 # flags '..\tools\windows.xml -m comtypes -m comtypes.automation -w -r .*TypeLibEx -r .*TypeLib -o typeinfo.py'
 # then hacked manually
+import ctypes
 import sys
-from typing import Any, overload, TypeVar, TYPE_CHECKING
-from typing import List, Type, Tuple
-from typing import Optional, Union as _UnionT
-from typing import Callable, Sequence
 import weakref
-
-import ctypes
 from ctypes import HRESULT, POINTER, _Pointer, byref, c_int, c_void_p, c_wchar_p
-from ctypes.wintypes import DWORD, LONG, UINT, ULONG, WCHAR, WORD, INT, SHORT, USHORT
-from comtypes import BSTR, _CData, COMMETHOD, GUID, IID, IUnknown, STDMETHOD
-from comtypes.automation import DISPID, LCID, SCODE
-from comtypes.automation import DISPPARAMS, EXCEPINFO, VARIANT, VARIANTARG, VARTYPE
+from ctypes.wintypes import (
+    DWORD,
+    HMODULE,
+    INT,
+    LONG,
+    LPWSTR,
+    SHORT,
+    UINT,
+    ULONG,
+    USHORT,
+    WCHAR,
+    WORD,
+)
+from typing import (
+    TYPE_CHECKING,
+    Any,
+    Callable,
+    List,
+    Optional,
+    Sequence,
+    Tuple,
+    Type,
+    TypeVar,
+    overload,
+)
+from typing import Union as _UnionT
+
+from comtypes import BSTR, COMMETHOD, GUID, IID, STDMETHOD, IUnknown, _CData
+from comtypes.automation import (
+    DISPID,
+    DISPPARAMS,
+    EXCEPINFO,
+    LCID,
+    SCODE,
+    VARIANT,
+    VARIANTARG,
+    VARTYPE,
+)
 
 if TYPE_CHECKING:
     from comtypes import hints  # type: ignore
@@ -666,6 +695,22 @@ def QueryPathOfRegTypeLib(
     return pathname.value.split("\0")[0]
 
 
+_GetModuleFileNameW = ctypes.windll.kernel32.GetModuleFileNameW
+_GetModuleFileNameW.argtypes = HMODULE, LPWSTR, DWORD
+_GetModuleFileNameW.restype = DWORD
+
+
+def GetModuleFileName(handle: Optional[int], maxsize: int) -> str:
+    """Returns the fullpath of the loaded module specified by the handle.
+    If the handle is NULL, returns the executable file path of the current process.
+
+    https://learn.microsoft.com/ja-jp/windows/win32/api/libloaderapi/nf-libloaderapi-loadlibraryw
+    """
+    buf = ctypes.create_unicode_buffer(maxsize)
+    length = _GetModuleFileNameW(handle, buf, maxsize)
+    return buf.value[:length]
+
+
 ################################################################
 # Structures