diff --git a/Lib/test/test_os.py b/Lib/test/test_os.py
--- a/Lib/test/test_os.py
+++ b/Lib/test/test_os.py
@@ -23,6 +23,16 @@
 warnings.filterwarnings("ignore", "tempnam", RuntimeWarning, __name__)
 warnings.filterwarnings("ignore", "tmpnam", RuntimeWarning, __name__)
 
+supports_unicode_filenames = True
+if not os.path.supports_unicode_filenames:
+    try:
+        test_support.TESTFN_UNICODE.encode(test_support.TESTFN_ENCODING)
+    except (AttributeError, UnicodeError, TypeError):
+        # Either the file system encoding is None, or the file name
+        # cannot be encoded in the file system encoding.
+        supports_unicode_filenames = False
+
+
 # Tests creating TESTFN
 class FileTests(unittest.TestCase):
     def setUp(self):
@@ -295,6 +305,16 @@
         except TypeError:
             pass
 
+    @unittest.skipUnless(hasattr(os, 'statvfs'), 'test needs os.statvfs()')
+    @unittest.skipUnless(supports_unicode_filenames,
+                         "unicode file names are not supported")
+    def test_statvfs_unicode(self):
+        fname = test_support.TESTFN_UNICODE
+        test_support.unlink(fname)
+        with open(fname, 'w'):
+            self.addCleanup(test_support.unlink, fname)
+        os.statvfs(fname)
+
     def test_utime_dir(self):
         delta = 1000000
         st = os.stat(test_support.TESTFN)
diff --git a/Modules/posixmodule.c b/Modules/posixmodule.c
--- a/Modules/posixmodule.c
+++ b/Modules/posixmodule.c
@@ -7447,7 +7447,8 @@
     char *path;
     int res;
     struct statvfs st;
-    if (!PyArg_ParseTuple(args, "s:statvfs", &path))
+    if (!PyArg_ParseTuple(args, "et:statvfs",
+                          Py_FileSystemDefaultEncoding, &path))
         return NULL;
     Py_BEGIN_ALLOW_THREADS
     res = statvfs(path, &st);