diff --git a/importlib_resources/_compat.py b/importlib_resources/_compat.py
index a93a882..d7e9f0d 100644
--- a/importlib_resources/_compat.py
+++ b/importlib_resources/_compat.py
@@ -4,6 +4,7 @@
 import os
 import sys
 import pathlib
+import warnings
 from contextlib import suppress
 from typing import Union
 
@@ -107,3 +108,19 @@ def wrap_spec(package):
 else:
     # PathLike is only subscriptable at runtime in 3.9+
     StrPath = Union[str, "os.PathLike[str]"]
+
+
+def ensure_traversable(path):
+    """
+    Convert deprecated string arguments to traversables (pathlib.Path).
+    """
+    if not isinstance(path, str):
+        return path
+
+    warnings.warn(
+        "String arguments are deprecated. Pass a Traversable instead.",
+        DeprecationWarning,
+        stacklevel=3,
+    )
+
+    return pathlib.Path(path)
diff --git a/importlib_resources/readers.py b/importlib_resources/readers.py
index 51d030a..dc1ec94 100644
--- a/importlib_resources/readers.py
+++ b/importlib_resources/readers.py
@@ -6,7 +6,7 @@
 from . import abc
 
 from ._itertools import only
-from ._compat import ZipPath
+from ._compat import ZipPath, ensure_traversable
 
 
 def remove_duplicates(items):
@@ -62,7 +62,7 @@ class MultiplexedPath(abc.Traversable):
     """
 
     def __init__(self, *paths):
-        self._paths = list(map(pathlib.Path, remove_duplicates(paths)))
+        self._paths = list(map(ensure_traversable, remove_duplicates(paths)))
         if not self._paths:
             message = 'MultiplexedPath must contain at least one path'
             raise FileNotFoundError(message)
diff --git a/importlib_resources/tests/test_reader.py b/importlib_resources/tests/test_reader.py
index e2bdf19..a1eadb2 100644
--- a/importlib_resources/tests/test_reader.py
+++ b/importlib_resources/tests/test_reader.py
@@ -10,8 +10,7 @@
 class MultiplexedPathTest(unittest.TestCase):
     @classmethod
     def setUpClass(cls):
-        path = pathlib.Path(__file__).parent / 'namespacedata01'
-        cls.folder = str(path)
+        cls.folder = pathlib.Path(__file__).parent / 'namespacedata01'
 
     def test_init_no_paths(self):
         with self.assertRaises(FileNotFoundError):
@@ -19,7 +18,7 @@ def test_init_no_paths(self):
 
     def test_init_file(self):
         with self.assertRaises(NotADirectoryError):
-            MultiplexedPath(os.path.join(self.folder, 'binary.file'))
+            MultiplexedPath(self.folder / 'binary.file')
 
     def test_iterdir(self):
         contents = {path.name for path in MultiplexedPath(self.folder).iterdir()}
@@ -30,7 +29,7 @@ def test_iterdir(self):
         self.assertEqual(contents, {'binary.file', 'utf-16.file', 'utf-8.file'})
 
     def test_iterdir_duplicate(self):
-        data01 = os.path.abspath(os.path.join(__file__, '..', 'data01'))
+        data01 = pathlib.Path(__file__).parent.joinpath('data01')
         contents = {
             path.name for path in MultiplexedPath(self.folder, data01).iterdir()
         }
@@ -60,8 +59,8 @@ def test_open_file(self):
             path.open()
 
     def test_join_path(self):
-        prefix = os.path.abspath(os.path.join(__file__, '..'))
-        data01 = os.path.join(prefix, 'data01')
+        data01 = pathlib.Path(__file__).parent.joinpath('data01')
+        prefix = str(data01.parent)
         path = MultiplexedPath(self.folder, data01)
         self.assertEqual(
             str(path.joinpath('binary.file'))[len(prefix) + 1 :],
@@ -82,9 +81,9 @@ def test_join_path_compound(self):
         assert not path.joinpath('imaginary/foo.py').exists()
 
     def test_join_path_common_subdir(self):
-        prefix = os.path.abspath(os.path.join(__file__, '..'))
-        data01 = os.path.join(prefix, 'data01')
-        data02 = os.path.join(prefix, 'data02')
+        data01 = pathlib.Path(__file__).parent.joinpath('data01')
+        data02 = pathlib.Path(__file__).parent.joinpath('data02')
+        prefix = str(data01.parent)
         path = MultiplexedPath(data01, data02)
         self.assertIsInstance(path.joinpath('subdirectory'), MultiplexedPath)
         self.assertEqual(
diff --git a/importlib_resources/tests/test_resource.py b/importlib_resources/tests/test_resource.py
index 4036805..850d029 100644
--- a/importlib_resources/tests/test_resource.py
+++ b/importlib_resources/tests/test_resource.py
@@ -3,6 +3,8 @@
 import importlib_resources as resources
 import pathlib
 
+import pytest
+
 from . import data01
 from . import util
 from importlib import import_module
@@ -209,5 +211,14 @@ def tearDownClass(cls):
         sys.path.remove(cls.site_dir)
 
 
+@pytest.mark.xfail
+class ResourceFromNamespaceZipTests(
+    util.ZipSetupBase,
+    ResourceFromNamespaceTests,
+    unittest.TestCase,
+):
+    ZIP_MODULE = 'namespacedata01'
+
+
 if __name__ == '__main__':
     unittest.main()
diff --git a/newsfragments/+13deb64a.feature.rst b/newsfragments/+13deb64a.feature.rst
new file mode 100644
index 0000000..a765911
--- /dev/null
+++ b/newsfragments/+13deb64a.feature.rst
@@ -0,0 +1 @@
+MultiplexedPath now expects Traversable paths. String arguments to MultiplexedPath are now deprecated.
\ No newline at end of file