@@ -35,7 +35,7 @@
 from git.objects import Submodule, RootModule, Commit
 from git.refs import HEAD, Head, Reference, TagReference
 from git.remote import Remote, add_progress, to_progress_instance
-from git.util import Actor, finalize_process
+from git.util import Actor, finalize_process, decygpath
 
 from .fun import rev_parse, is_git_dir, find_git_dir, touch
 
@@ -99,6 +99,8 @@ def __init__(self, path=None, odbt=DefaultDBType, search_parent_directories=Fals
                 repo = Repo("~/Development/git-python.git")
                 repo = Repo("$REPOSITORIES/Development/git-python.git")
 
+            In *Cygwin*, path may be a `'cygdrive/...'` prefixed path.
+            
         :param odbt:
             Object DataBase type - a type which is constructed by providing
             the directory containing the database objects, i.e. .git/objects. It will
@@ -111,6 +113,9 @@ def __init__(self, path=None, odbt=DefaultDBType, search_parent_directories=Fals
         :raise InvalidGitRepositoryError:
         :raise NoSuchPathError:
         :return: git.Repo """
+        if path and Git.is_cygwin():
+            path = decygpath(path)
+
         epath = _expand_path(path or os.getcwd())
         self.git = None  # should be set for __del__ not to fail in case we raise
         if not os.path.exists(epath):
 
@@ -50,7 +50,7 @@
     assert_true,
     raises
 )
-from git.util import HIDE_WINDOWS_KNOWN_ERRORS
+from git.util import HIDE_WINDOWS_KNOWN_ERRORS, cygpath
 from git.test.lib import with_rw_directory
 from git.util import join_path_native, rmtree, rmfile
 from gitdb.util import bin_to_hex
@@ -913,6 +913,8 @@ def test_work_tree_unsupported(self, rw_dir):
         rw_master = self.rorepo.clone(join_path_native(rw_dir, 'master_repo'))
         rw_master.git.checkout('HEAD~10')
         worktree_path = join_path_native(rw_dir, 'worktree_repo')
+        if Git.is_cygwin():
+            worktree_path = cygpath(worktree_path)
         try:
             rw_master.git.worktree('add', worktree_path, 'master')
         except Exception as ex:
 
@@ -29,6 +29,34 @@
     Actor,
     IterableList,
     cygpath,
+    decygpath
+)
+
+
+_norm_cygpath_pairs = (
+    (r'foo\bar', 'foo/bar'),
+    (r'foo/bar', 'foo/bar'),
+
+    (r'C:\Users', '/cygdrive/c/Users'),
+    (r'C:\d/e', '/cygdrive/c/d/e'),
+
+    ('C:\\', '/cygdrive/c/'),
+
+    (r'\\server\C$\Users', '//server/C$/Users'),
+    (r'\\server\C$', '//server/C$'),
+    ('\\\\server\\c$\\', '//server/c$/'),
+    (r'\\server\BAR/', '//server/BAR/'),
+
+    (r'D:/Apps', '/cygdrive/d/Apps'),
+    (r'D:/Apps\fOO', '/cygdrive/d/Apps/fOO'),
+    (r'D:\Apps/123', '/cygdrive/d/Apps/123'),
+)
+
+_unc_cygpath_pairs = (
+    (r'\\?\a:\com', '/cygdrive/a/com'),
+    (r'\\?\a:/com', '/cygdrive/a/com'),
+
+    (r'\\?\UNC\server\D$\Apps', '//server/D$/Apps'),
 )
 
 
@@ -54,46 +82,45 @@ def setup(self):
             "array": [42],
         }
 
+    @skipIf(not is_win, "Paths specifically for Windows.")
+    @ddt.idata(_norm_cygpath_pairs + _unc_cygpath_pairs)
+    def test_cygpath_ok(self, case):
+        wpath, cpath = case
+        cwpath = cygpath(wpath)
+        self.assertEqual(cwpath, cpath, wpath)
+
     @skipIf(not is_win, "Paths specifically for Windows.")
     @ddt.data(
-        (r'foo\bar', 'foo/bar'),
-        (r'foo/bar', 'foo/bar'),
         (r'./bar', 'bar'),
         (r'.\bar', 'bar'),
         (r'../bar', '../bar'),
         (r'..\bar', '../bar'),
         (r'../bar/.\foo/../chu', '../bar/chu'),
-
-        (r'C:\Users', '/cygdrive/c/Users'),
-        (r'C:\d/e', '/cygdrive/c/d/e'),
-
-        (r'\\?\a:\com', '/cygdrive/a/com'),
-        (r'\\?\a:/com', '/cygdrive/a/com'),
-
-        (r'\\server\C$\Users', '//server/C$/Users'),
-        (r'\\server\C$', '//server/C$'),
-        (r'\\server\BAR/', '//server/BAR/'),
-        (r'\\?\UNC\server\D$\Apps', '//server/D$/Apps'),
-
-        (r'D:/Apps', '/cygdrive/d/Apps'),
-        (r'D:/Apps\fOO', '/cygdrive/d/Apps/fOO'),
-        (r'D:\Apps/123', '/cygdrive/d/Apps/123'),
     )
-    def test_cygpath_ok(self, case):
+    def test_cygpath_norm_ok(self, case):
         wpath, cpath = case
-        self.assertEqual(cygpath(wpath), cpath or wpath)
+        cwpath = cygpath(wpath)
+        self.assertEqual(cwpath, cpath or wpath, wpath)
 
     @skipIf(not is_win, "Paths specifically for Windows.")
     @ddt.data(
-        (r'C:Relative', None),
-        (r'D:Apps\123', None),
-        (r'D:Apps/123', None),
-        (r'\\?\a:rel', None),
-        (r'\\share\a:rel', None),
+        r'C:',
+        r'C:Relative',
+        r'D:Apps\123',
+        r'D:Apps/123',
+        r'\\?\a:rel',
+        r'\\share\a:rel',
     )
-    def test_cygpath_invalids(self, case):
+    def test_cygpath_invalids(self, wpath):
+        cwpath = cygpath(wpath)
+        self.assertEqual(cwpath, wpath.replace('\\', '/'), wpath)
+
+    @skipIf(not is_win, "Paths specifically for Windows.")
+    @ddt.idata(_norm_cygpath_pairs)
+    def test_decygpath(self, case):
         wpath, cpath = case
-        self.assertEqual(cygpath(wpath), cpath or wpath.replace('\\', '/'))
+        wcpath = decygpath(cpath)
+        self.assertEqual(wcpath, wpath.replace('/', '\\'), cpath)
 
     def test_it_should_dashify(self):
         assert_equal('this-is-my-argument', dashify('this_is_my_argument'))
 
@@ -222,7 +222,7 @@ def _cygexpath(drive, path):
         #  It's an error, leave it alone just slashes)
         p = path
     else:
-        p = osp.normpath(osp.expandvars(os.path.expanduser(path)))
+        p = path and osp.normpath(osp.expandvars(os.path.expanduser(path)))
         if osp.isabs(p):
             if drive:
                 # Confusing, maybe a remote system should expand vars.
@@ -278,6 +278,18 @@ def cygpath(path):
     return path
 
 
+_decygpath_regex = re.compile(r"/cygdrive/(\w)(/.*)?")
+
+
+def decygpath(path):
+    m = _decygpath_regex.match(path)
+    if m:
+        drive, rest_path = m.groups()
+        path = '%s:%s' % (drive.upper(), rest_path or '')
+
+    return path.replace('/', '\\')
+
+
 #: Store boolean flags denoting if a specific Git executable
 #: is from a Cygwin installation (since `cache_lru()` unsupported on PY2).
 _is_cygwin_cache = {}