diff --git a/sphinx/directives/code.py b/sphinx/directives/code.py
index e0df09d2b5f..b68f6e1a729 100644
--- a/sphinx/directives/code.py
+++ b/sphinx/directives/code.py
@@ -13,9 +13,12 @@
 from sphinx.locale import __
 from sphinx.util import logging
 from sphinx.util._lines import parse_line_num_spec
+from sphinx.util._pathlib import _StrPath
 from sphinx.util.docutils import SphinxDirective
 
 if TYPE_CHECKING:
+    import os
+
     from docutils.nodes import Element, Node
 
     from sphinx.application import Sphinx
@@ -197,8 +200,10 @@ class LiteralIncludeReader:
         ('diff', 'end-at'),
     ]
 
-    def __init__(self, filename: str, options: dict[str, Any], config: Config) -> None:
-        self.filename = filename
+    def __init__(
+        self, filename: str | os.PathLike[str], options: dict[str, Any], config: Config
+    ) -> None:
+        self.filename = _StrPath(filename)
         self.options = options
         self.encoding = options.get('encoding', config.source_encoding)
         self.lineno_start = self.options.get('lineno-start', 1)
@@ -212,8 +217,9 @@ def parse_options(self) -> None:
                 raise ValueError(msg)
 
     def read_file(
-        self, filename: str, location: tuple[str, int] | None = None
+        self, filename: str | os.PathLike[str], location: tuple[str, int] | None = None
     ) -> list[str]:
+        filename = _StrPath(filename)
         try:
             with open(filename, encoding=self.encoding, errors='strict') as f:
                 text = f.read()
@@ -222,11 +228,11 @@ def read_file(
 
                 return text.splitlines(True)
         except OSError as exc:
-            msg = __('Include file %r not found or reading it failed') % filename
+            msg = __("Include file '%s' not found or reading it failed") % filename
             raise OSError(msg) from exc
         except UnicodeError as exc:
             msg = __(
-                'Encoding %r used for reading included file %r seems to '
+                "Encoding %r used for reading included file '%s' seems to "
                 'be wrong, try giving an :encoding: option'
             ) % (self.encoding, filename)
             raise UnicodeError(msg) from exc
diff --git a/sphinx/pycode/__init__.py b/sphinx/pycode/__init__.py
index da078b2f0f0..4094d7a9b8b 100644
--- a/sphinx/pycode/__init__.py
+++ b/sphinx/pycode/__init__.py
@@ -2,13 +2,15 @@
 
 from __future__ import annotations
 
+import os
 import tokenize
 from importlib import import_module
 from os import path
-from typing import TYPE_CHECKING, Any
+from typing import TYPE_CHECKING, Any, Literal
 
 from sphinx.errors import PycodeError
 from sphinx.pycode.parser import Parser
+from sphinx.util._pathlib import _StrPath
 
 if TYPE_CHECKING:
     from inspect import Signature
@@ -23,7 +25,7 @@ class ModuleAnalyzer:
     tags: dict[str, tuple[str, int, int]]
 
     # cache for analyzer objects -- caches both by module and file name
-    cache: dict[tuple[str, str], Any] = {}
+    cache: dict[tuple[Literal['file', 'module'], str | _StrPath], Any] = {}
 
     @staticmethod
     def get_module_source(modname: str) -> tuple[str | None, str | None]:
@@ -81,8 +83,9 @@ def for_string(
 
     @classmethod
     def for_file(
-        cls: type[ModuleAnalyzer], filename: str, modname: str
+        cls: type[ModuleAnalyzer], filename: str | os.PathLike[str], modname: str
     ) -> ModuleAnalyzer:
+        filename = _StrPath(filename)
         if ('file', filename) in cls.cache:
             return cls.cache['file', filename]
         try:
@@ -114,9 +117,11 @@ def for_module(cls: type[ModuleAnalyzer], modname: str) -> ModuleAnalyzer:
         cls.cache['module', modname] = obj
         return obj
 
-    def __init__(self, source: str, modname: str, srcname: str) -> None:
+    def __init__(
+        self, source: str, modname: str, srcname: str | os.PathLike[str]
+    ) -> None:
         self.modname = modname  # name of the module
-        self.srcname = srcname  # name of the source file
+        self.srcname = str(srcname)  # name of the source file
 
         # cache the source code as well
         self.code = source
diff --git a/tests/roots/test-apidoc-toc/mypackage/main.py b/tests/roots/test-apidoc-toc/mypackage/main.py
index f532813a722..1f6d1376cbb 100755
--- a/tests/roots/test-apidoc-toc/mypackage/main.py
+++ b/tests/roots/test-apidoc-toc/mypackage/main.py
@@ -1,6 +1,6 @@
 #!/usr/bin/env python3
 
-import os
+from pathlib import Path
 
 import mod_resource
 import mod_something
@@ -8,8 +8,6 @@
 if __name__ == "__main__":
     print(f"Hello, world! -> something returns: {mod_something.something()}")
 
-    res_path = \
-        os.path.join(os.path.dirname(mod_resource.__file__), 'resource.txt')
-    with open(res_path, encoding='utf-8') as f:
-        text = f.read()
+    res_path = Path(mod_resource.__file__).parent / 'resource.txt'
+    text = res_path.read_text(encoding='utf-8')
     print(f"From mod_resource:resource.txt -> {text}")
diff --git a/tests/roots/test-theming/test_theme/__init__.py b/tests/roots/test-theming/test_theme/__init__.py
index 13bdc4b2c13..e69de29bb2d 100644
--- a/tests/roots/test-theming/test_theme/__init__.py
+++ b/tests/roots/test-theming/test_theme/__init__.py
@@ -1,5 +0,0 @@
-import os
-
-
-def get_path():
-    return os.path.dirname(os.path.abspath(__file__))
diff --git a/tests/test_builders/test_build_epub.py b/tests/test_builders/test_build_epub.py
index d54903507a8..3c2be6323d4 100644
--- a/tests/test_builders/test_build_epub.py
+++ b/tests/test_builders/test_build_epub.py
@@ -450,8 +450,8 @@ def test_run_epubcheck(app):
     if not runnable(['java', '-version']):
         pytest.skip('Unable to run Java; skipping test')
 
-    epubcheck = os.environ.get('EPUBCHECK_PATH', '/usr/share/java/epubcheck.jar')
-    if not os.path.exists(epubcheck):
+    epubcheck = Path(os.environ.get('EPUBCHECK_PATH', '/usr/share/java/epubcheck.jar'))
+    if not epubcheck.exists():
         pytest.skip('Could not find epubcheck; skipping test')
 
     try:
diff --git a/tests/test_builders/test_build_gettext.py b/tests/test_builders/test_build_gettext.py
index e9ed4afb90f..00d7f826ecc 100644
--- a/tests/test_builders/test_build_gettext.py
+++ b/tests/test_builders/test_build_gettext.py
@@ -1,10 +1,10 @@
 """Test the build process with gettext builder with the test root."""
 
 import gettext
-import os
 import re
 import subprocess
 from contextlib import chdir
+from pathlib import Path
 from subprocess import CalledProcessError
 
 import pytest
@@ -94,7 +94,7 @@ def test_msgfmt(app):
                 'msgfmt',
                 'en_US.po',
                 '-o',
-                os.path.join('en', 'LC_MESSAGES', 'test_root.mo'),
+                Path('en', 'LC_MESSAGES', 'test_root.mo'),
             ]
             subprocess.run(args, capture_output=True, check=True)
         except OSError:
diff --git a/tests/test_command_line.py b/tests/test_command_line.py
index 63fb9e036d3..e346784b5dd 100644
--- a/tests/test_command_line.py
+++ b/tests/test_command_line.py
@@ -1,7 +1,7 @@
 from __future__ import annotations
 
-import os.path
 import sys
+from pathlib import Path
 from typing import Any
 
 import pytest
@@ -52,8 +52,8 @@
 EXPECTED_MAKE_MODE = {
     'builder': 'html',
     'sourcedir': 'source_dir',
-    'outputdir': os.path.join('build_dir', 'html'),
-    'doctreedir': os.path.join('build_dir', 'doctrees'),
+    'outputdir': str(Path('build_dir', 'html')),
+    'doctreedir': str(Path('build_dir', 'doctrees')),
     'filenames': ['filename1', 'filename2'],
     'freshenv': True,
     'noconfig': True,
diff --git a/tests/test_directives/test_directive_code.py b/tests/test_directives/test_directive_code.py
index 65e16b805bd..dacf8a3b334 100644
--- a/tests/test_directives/test_directive_code.py
+++ b/tests/test_directives/test_directive_code.py
@@ -1,7 +1,5 @@
 """Test the code-block directive."""
 
-import os.path
-
 import pytest
 from docutils import nodes
 
@@ -257,12 +255,13 @@ def test_LiteralIncludeReader_tabwidth_dedent(testroot):
 
 
 def test_LiteralIncludeReader_diff(testroot, literal_inc_path):
-    options = {'diff': testroot / 'literal-diff.inc'}
+    literal_diff_path = testroot / 'literal-diff.inc'
+    options = {'diff': literal_diff_path}
     reader = LiteralIncludeReader(literal_inc_path, options, DUMMY_CONFIG)
     content, lines = reader.read()
     assert content == (
-        '--- ' + os.path.join(testroot, 'literal-diff.inc') + '\n'
-        '+++ ' + os.path.join(testroot, 'literal.inc') + '\n'
+        f'--- {literal_diff_path}\n'
+        f'+++ {literal_inc_path}\n'
         '@@ -6,8 +6,8 @@\n'
         '     pass\n'
         ' \n'
diff --git a/tests/test_environment/test_environment.py b/tests/test_environment/test_environment.py
index b711fd879c4..64487b8c3f6 100644
--- a/tests/test_environment/test_environment.py
+++ b/tests/test_environment/test_environment.py
@@ -1,6 +1,5 @@
 """Test the BuildEnvironment class."""
 
-import os
 import shutil
 from pathlib import Path
 
@@ -41,8 +40,8 @@ def test_config_status(make_app, app_params):
 
     # incremental build (config entry changed)
     app3 = make_app(*args, confoverrides={'root_doc': 'indexx'}, **kwargs)
-    fname = os.path.join(app3.srcdir, 'index.rst')
-    assert os.path.isfile(fname)
+    fname = app3.srcdir / 'index.rst'
+    assert fname.is_file()
     shutil.move(fname, fname[:-4] + 'x.rst')
     assert app3.env.config_status == CONFIG_CHANGED
     app3.build()
diff --git a/tests/test_extensions/test_ext_apidoc.py b/tests/test_extensions/test_ext_apidoc.py
index 6440da1f6ce..3886617c742 100644
--- a/tests/test_extensions/test_ext_apidoc.py
+++ b/tests/test_extensions/test_ext_apidoc.py
@@ -1,6 +1,5 @@
 """Test the sphinx.apidoc module."""
 
-import os.path
 from collections import namedtuple
 from pathlib import Path
 
@@ -732,7 +731,7 @@ def test_no_duplicates(rootdir, tmp_path):
         apidoc_main(['-o', str(outdir), '-T', str(package), '--implicit-namespaces'])
 
         # Ensure the module has been documented
-        assert os.path.isfile(outdir / 'fish_licence.rst')
+        assert (outdir / 'fish_licence.rst').is_file()
 
         # Ensure the submodule only appears once
         text = (outdir / 'fish_licence.rst').read_text(encoding='utf-8')
diff --git a/tests/test_extensions/test_ext_autodoc_configs.py b/tests/test_extensions/test_ext_autodoc_configs.py
index 58e90eba42c..c3911b8533c 100644
--- a/tests/test_extensions/test_ext_autodoc_configs.py
+++ b/tests/test_extensions/test_ext_autodoc_configs.py
@@ -2,7 +2,9 @@
 
 import platform
 import sys
+from collections.abc import Iterator
 from contextlib import contextmanager
+from pathlib import Path
 
 import pytest
 
@@ -19,7 +21,7 @@
 
 
 @contextmanager
-def overwrite_file(path, content):
+def overwrite_file(path: Path, content: str) -> Iterator[None]:
     current_content = path.read_bytes() if path.exists() else None
     try:
         path.write_text(content, encoding='utf-8')
diff --git a/tests/test_extensions/test_ext_inheritance_diagram.py b/tests/test_extensions/test_ext_inheritance_diagram.py
index a3e0b9238fa..2aa4ff99188 100644
--- a/tests/test_extensions/test_ext_inheritance_diagram.py
+++ b/tests/test_extensions/test_ext_inheritance_diagram.py
@@ -1,9 +1,9 @@
 """Test sphinx.ext.inheritance_diagram extension."""
 
-import os
 import re
 import sys
 import zlib
+from pathlib import Path
 
 import pytest
 
@@ -26,7 +26,7 @@ def test_inheritance_diagram(app):
     def new_run(self):
         result = orig_run(self)
         node = result[0]
-        source = os.path.basename(node.document.current_source).replace('.rst', '')
+        source = Path(node.document.current_source).stem
         graphs[source] = node['graph']
         return result
 
diff --git a/tests/test_intl/test_intl.py b/tests/test_intl/test_intl.py
index b53a07f75e3..077516b0a05 100644
--- a/tests/test_intl/test_intl.py
+++ b/tests/test_intl/test_intl.py
@@ -4,7 +4,6 @@
 """
 
 import os
-import os.path
 import re
 import shutil
 import time
diff --git a/tests/test_pycode/test_pycode.py b/tests/test_pycode/test_pycode.py
index 87e5ca57dff..3a34d6f3a0f 100644
--- a/tests/test_pycode/test_pycode.py
+++ b/tests/test_pycode/test_pycode.py
@@ -1,7 +1,7 @@
 """Test pycode."""
 
-import os
 import sys
+from pathlib import Path
 
 import pytest
 
@@ -9,7 +9,7 @@
 from sphinx.errors import PycodeError
 from sphinx.pycode import ModuleAnalyzer
 
-SPHINX_MODULE_PATH = os.path.splitext(sphinx.__file__)[0] + '.py'
+SPHINX_MODULE_PATH = Path(sphinx.__file__).resolve().with_suffix('.py')
 
 
 def test_ModuleAnalyzer_get_module_source():
@@ -40,7 +40,7 @@ def test_ModuleAnalyzer_for_file():
 def test_ModuleAnalyzer_for_module(rootdir):
     analyzer = ModuleAnalyzer.for_module('sphinx')
     assert analyzer.modname == 'sphinx'
-    assert analyzer.srcname in {SPHINX_MODULE_PATH, os.path.abspath(SPHINX_MODULE_PATH)}
+    assert analyzer.srcname == str(SPHINX_MODULE_PATH)
 
     saved_path = sys.path.copy()
     sys.path.insert(0, str(rootdir / 'test-pycode'))
diff --git a/tests/test_quickstart.py b/tests/test_quickstart.py
index 7225775d19b..07a61689575 100644
--- a/tests/test_quickstart.py
+++ b/tests/test_quickstart.py
@@ -3,7 +3,6 @@
 import time
 from collections.abc import Callable
 from io import StringIO
-from os import path
 from pathlib import Path
 from typing import Any
 
@@ -260,10 +259,7 @@ def test_extensions(tmp_path):
 def test_exits_when_existing_confpy(monkeypatch):
     # The code detects existing conf.py with path.is_file()
     # so we mock it as True with pytest's monkeypatch
-    def mock_isfile(path):
-        return True
-
-    monkeypatch.setattr(path, 'isfile', mock_isfile)
+    monkeypatch.setattr('os.path.isfile', lambda path: True)
 
     qs.term_input = mock_input({
         'Please enter a new root path (or just Enter to exit)': '',
diff --git a/tests/test_util/test_util.py b/tests/test_util/test_util.py
index b36ad0ee93c..b04c30e7aa8 100644
--- a/tests/test_util/test_util.py
+++ b/tests/test_util/test_util.py
@@ -1,16 +1,12 @@
 """Tests util functions."""
 
-import os
-import tempfile
-
 from sphinx.util.osutil import ensuredir
 
 
-def test_ensuredir():
-    with tempfile.TemporaryDirectory() as tmp_path:
-        # Does not raise an exception for an existing directory.
-        ensuredir(tmp_path)
+def test_ensuredir(tmp_path):
+    # Does not raise an exception for an existing directory.
+    ensuredir(tmp_path)
 
-        path = os.path.join(tmp_path, 'a', 'b', 'c')
-        ensuredir(path)
-        assert os.path.isdir(path)
+    path = tmp_path / 'a' / 'b' / 'c'
+    ensuredir(path)
+    assert path.is_dir()
diff --git a/tests/test_util/test_util_logging.py b/tests/test_util/test_util_logging.py
index 9d3e5023aea..5a9e0be5ada 100644
--- a/tests/test_util/test_util_logging.py
+++ b/tests/test_util/test_util_logging.py
@@ -2,12 +2,12 @@
 
 import codecs
 import os
-import os.path
+from pathlib import Path
 
 import pytest
 from docutils import nodes
 
-from sphinx.util import logging, osutil
+from sphinx.util import logging
 from sphinx.util.console import colorize, strip_colors
 from sphinx.util.logging import is_suppressed_warning, prefixed_warnings
 from sphinx.util.parallel import ParallelTasks
@@ -360,15 +360,15 @@ def test_get_node_location_abspath():
     # Ensure that node locations are reported as an absolute path,
     # even if the source attribute is a relative path.
 
-    relative_filename = os.path.join('relative', 'path.txt')
-    absolute_filename = osutil.abspath(relative_filename)
+    relative_filename = Path('relative', 'path.txt')
+    absolute_filename = relative_filename.resolve()
 
     n = nodes.Node()
-    n.source = relative_filename
+    n.source = str(relative_filename)
 
     location = logging.get_node_location(n)
 
-    assert location == absolute_filename + ':'
+    assert location == f'{absolute_filename}:'
 
 
 @pytest.mark.sphinx('html', testroot='root', confoverrides={'show_warning_types': True})