diff --git a/sphinx/builders/html/__init__.py b/sphinx/builders/html/__init__.py
index 6955caf16..06917232f 100644
--- a/sphinx/builders/html/__init__.py
+++ b/sphinx/builders/html/__init__.py
@@ -9,7 +9,6 @@ import os
 import posixpath
 import re
 import sys
-import time
 import types
 import warnings
 from os import path
@@ -40,13 +39,21 @@ from sphinx.locale import _, __
 from sphinx.search import js_index
 from sphinx.theming import HTMLThemeFactory
 from sphinx.util import isurl, logging
+from sphinx.util._timestamps import _format_rfc3339_microseconds
 from sphinx.util.display import progress_message, status_iterator
 from sphinx.util.docutils import new_document
 from sphinx.util.fileutil import copy_asset
 from sphinx.util.i18n import format_date
 from sphinx.util.inventory import InventoryFile
 from sphinx.util.matching import DOTFILES, Matcher, patmatch
-from sphinx.util.osutil import SEP, copyfile, ensuredir, os_path, relative_uri
+from sphinx.util.osutil import (
+    SEP,
+    _last_modified_time,
+    copyfile,
+    ensuredir,
+    os_path,
+    relative_uri,
+)
 from sphinx.writers.html import HTMLWriter
 from sphinx.writers.html5 import HTML5Translator
 
@@ -397,7 +404,7 @@ class StandaloneHTMLBuilder(Builder):
             pass
 
         if self.templates:
-            template_mtime = self.templates.newest_template_mtime()
+            template_mtime = int(self.templates.newest_template_mtime() * 10**6)
         else:
             template_mtime = 0
         for docname in self.env.found_docs:
@@ -407,19 +414,19 @@ class StandaloneHTMLBuilder(Builder):
                 continue
             targetname = self.get_outfilename(docname)
             try:
-                targetmtime = path.getmtime(targetname)
+                targetmtime = _last_modified_time(targetname)
             except Exception:
                 targetmtime = 0
             try:
-                srcmtime = max(path.getmtime(self.env.doc2path(docname)), template_mtime)
+                srcmtime = max(_last_modified_time(self.env.doc2path(docname)), template_mtime)
                 if srcmtime > targetmtime:
                     logger.debug(
                         '[build target] targetname %r(%s), template(%s), docname %r(%s)',
                         targetname,
-                        _format_modified_time(targetmtime),
-                        _format_modified_time(template_mtime),
+                        _format_rfc3339_microseconds(targetmtime),
+                        _format_rfc3339_microseconds(template_mtime),
                         docname,
-                        _format_modified_time(path.getmtime(self.env.doc2path(docname))),
+                        _format_rfc3339_microseconds(_last_modified_time(self.env.doc2path(docname))),
                     )
                     yield docname
             except OSError:
@@ -1224,12 +1231,6 @@ def convert_html_css_files(app: Sphinx, config: Config) -> None:
     config.html_css_files = html_css_files
 
 
-def _format_modified_time(timestamp: float) -> str:
-    """Return an RFC 3339 formatted string representing the given timestamp."""
-    seconds, fraction = divmod(timestamp, 1)
-    return time.strftime("%Y-%m-%d %H:%M:%S", time.gmtime(seconds)) + f'.{fraction:.3f}'
-
-
 def convert_html_js_files(app: Sphinx, config: Config) -> None:
     """Convert string styled html_js_files to tuple styled one."""
     html_js_files: list[tuple[str, dict[str, str]]] = []
diff --git a/sphinx/builders/text.py b/sphinx/builders/text.py
index 483e7fade..ec0eecfb5 100644
--- a/sphinx/builders/text.py
+++ b/sphinx/builders/text.py
@@ -10,7 +10,11 @@ from docutils.io import StringOutput
 from sphinx.builders import Builder
 from sphinx.locale import __
 from sphinx.util import logging
-from sphinx.util.osutil import ensuredir, os_path
+from sphinx.util.osutil import (
+    _last_modified_time,
+    ensuredir,
+    os_path,
+)
 from sphinx.writers.text import TextTranslator, TextWriter
 
 if TYPE_CHECKING:
@@ -46,11 +50,11 @@ class TextBuilder(Builder):
                 continue
             targetname = path.join(self.outdir, docname + self.out_suffix)
             try:
-                targetmtime = path.getmtime(targetname)
+                targetmtime = _last_modified_time(targetname)
             except Exception:
                 targetmtime = 0
             try:
-                srcmtime = path.getmtime(self.env.doc2path(docname))
+                srcmtime = _last_modified_time(self.env.doc2path(docname))
                 if srcmtime > targetmtime:
                     yield docname
             except OSError:
diff --git a/sphinx/builders/xml.py b/sphinx/builders/xml.py
index 1f2c10571..947c7d279 100644
--- a/sphinx/builders/xml.py
+++ b/sphinx/builders/xml.py
@@ -12,7 +12,11 @@ from docutils.writers.docutils_xml import XMLTranslator
 from sphinx.builders import Builder
 from sphinx.locale import __
 from sphinx.util import logging
-from sphinx.util.osutil import ensuredir, os_path
+from sphinx.util.osutil import (
+    _last_modified_time,
+    ensuredir,
+    os_path,
+)
 from sphinx.writers.xml import PseudoXMLWriter, XMLWriter
 
 if TYPE_CHECKING:
@@ -52,11 +56,11 @@ class XMLBuilder(Builder):
                 continue
             targetname = path.join(self.outdir, docname + self.out_suffix)
             try:
-                targetmtime = path.getmtime(targetname)
+                targetmtime = _last_modified_time(targetname)
             except Exception:
                 targetmtime = 0
             try:
-                srcmtime = path.getmtime(self.env.doc2path(docname))
+                srcmtime = _last_modified_time(self.env.doc2path(docname))
                 if srcmtime > targetmtime:
                     yield docname
             except OSError:
diff --git a/sphinx/environment/__init__.py b/sphinx/environment/__init__.py
index 239db1f8f..4ef23cd8d 100644
--- a/sphinx/environment/__init__.py
+++ b/sphinx/environment/__init__.py
@@ -5,7 +5,6 @@ from __future__ import annotations
 import functools
 import os
 import pickle
-import time
 from collections import defaultdict
 from copy import copy
 from os import path
@@ -17,10 +16,11 @@ from sphinx.errors import BuildEnvironmentError, DocumentError, ExtensionError,
 from sphinx.locale import __
 from sphinx.transforms import SphinxTransformer
 from sphinx.util import DownloadFiles, FilenameUniqDict, logging
+from sphinx.util._timestamps import _format_rfc3339_microseconds
 from sphinx.util.docutils import LoggingReporter
 from sphinx.util.i18n import CatalogRepository, docname_to_domain
 from sphinx.util.nodes import is_translatable
-from sphinx.util.osutil import canon_path, os_path
+from sphinx.util.osutil import _last_modified_time, canon_path, os_path
 
 if TYPE_CHECKING:
     from collections.abc import Callable, Iterator
@@ -508,7 +508,8 @@ class BuildEnvironment:
                 if newmtime > mtime:
                     logger.debug('[build target] outdated %r: %s -> %s',
                                  docname,
-                                 _format_modified_time(mtime), _format_modified_time(newmtime))
+                                 _format_rfc3339_microseconds(mtime),
+                                 _format_rfc3339_microseconds(newmtime))
                     changed.add(docname)
                     continue
                 # finally, check the mtime of dependencies
@@ -528,7 +529,8 @@ class BuildEnvironment:
                             logger.debug(
                                 '[build target] outdated %r from dependency %r: %s -> %s',
                                 docname, deppath,
-                                _format_modified_time(mtime), _format_modified_time(depmtime),
+                                _format_rfc3339_microseconds(mtime),
+                                _format_rfc3339_microseconds(depmtime),
                             )
                             changed.add(docname)
                             break
@@ -756,26 +758,6 @@ class BuildEnvironment:
         self.events.emit('env-check-consistency', self)
 
 
-def _last_modified_time(filename: str | os.PathLike[str]) -> int:
-    """Return the last modified time of ``filename``.
-
-    The time is returned as integer microseconds.
-    The lowest common denominator of modern file-systems seems to be
-    microsecond-level precision.
-
-    We prefer to err on the side of re-rendering a file,
-    so we round up to the nearest microsecond.
-    """
-    # upside-down floor division to get the ceiling
-    return -(os.stat(filename).st_mtime_ns // -1_000)
-
-
-def _format_modified_time(timestamp: int) -> str:
-    """Return an RFC 3339 formatted string representing the given timestamp."""
-    seconds, fraction = divmod(timestamp, 10**6)
-    return time.strftime("%Y-%m-%d %H:%M:%S", time.gmtime(seconds)) + f'.{fraction // 1_000}'
-
-
 def _traverse_toctree(
     traversed: set[str],
     parent: str | None,
diff --git a/sphinx/ext/viewcode.py b/sphinx/ext/viewcode.py
index 39a08b66b..9991cf5d4 100644
--- a/sphinx/ext/viewcode.py
+++ b/sphinx/ext/viewcode.py
@@ -21,6 +21,7 @@ from sphinx.transforms.post_transforms import SphinxPostTransform
 from sphinx.util import logging
 from sphinx.util.display import status_iterator
 from sphinx.util.nodes import make_refnode
+from sphinx.util.osutil import _last_modified_time
 
 if TYPE_CHECKING:
     from collections.abc import Iterable, Iterator
@@ -231,7 +232,7 @@ def should_generate_module_page(app: Sphinx, modname: str) -> bool:
     page_filename = path.join(app.outdir, '_modules/', basename)
 
     try:
-        if path.getmtime(module_filename) <= path.getmtime(page_filename):
+        if _last_modified_time(module_filename) <= _last_modified_time(page_filename):
             # generation is not needed if the HTML page is newer than module file.
             return False
     except OSError:
diff --git a/sphinx/jinja2glue.py b/sphinx/jinja2glue.py
index 9746d3eab..ec75c6d96 100644
--- a/sphinx/jinja2glue.py
+++ b/sphinx/jinja2glue.py
@@ -2,6 +2,7 @@
 
 from __future__ import annotations
 
+import os
 from os import path
 from pprint import pformat
 from typing import TYPE_CHECKING, Any
@@ -12,7 +13,7 @@ from jinja2.utils import open_if_exists, pass_context
 
 from sphinx.application import TemplateBridge
 from sphinx.util import logging
-from sphinx.util.osutil import mtimes_of_files
+from sphinx.util.osutil import _last_modified_time
 
 if TYPE_CHECKING:
     from collections.abc import Callable, Iterator
@@ -127,11 +128,11 @@ class SphinxFileSystemLoader(FileSystemLoader):
         with f:
             contents = f.read().decode(self.encoding)
 
-        mtime = path.getmtime(filename)
+        mtime = _last_modified_time(filename)
 
         def uptodate() -> bool:
             try:
-                return path.getmtime(filename) == mtime
+                return _last_modified_time(filename) == mtime
             except OSError:
                 return False
 
@@ -203,7 +204,13 @@ class BuiltinTemplateLoader(TemplateBridge, BaseLoader):
         return self.environment.from_string(source).render(context)
 
     def newest_template_mtime(self) -> float:
-        return max(mtimes_of_files(self.pathchain, '.html'))
+        return max(
+            os.stat(os.path.join(root, sfile)).st_mtime_ns / 10**9
+            for dirname in self.pathchain
+            for root, _dirs, files in os.walk(dirname)
+            for sfile in files
+            if sfile.endswith('.html')
+        )
 
     # Loader interface
 
diff --git a/sphinx/util/__init__.py b/sphinx/util/__init__.py
index ccc37ae60..4271f9089 100644
--- a/sphinx/util/__init__.py
+++ b/sphinx/util/__init__.py
@@ -29,10 +29,8 @@ from sphinx.util.nodes import (  # NoQA: F401
 from sphinx.util.osutil import (  # NoQA: F401
     SEP,
     copyfile,
-    copytimes,
     ensuredir,
     make_filename,
-    mtimes_of_files,
     os_path,
     relative_uri,
 )
diff --git a/sphinx/util/_timestamps.py b/sphinx/util/_timestamps.py
new file mode 100644
index 000000000..32aca5232
--- /dev/null
+++ b/sphinx/util/_timestamps.py
@@ -0,0 +1,12 @@
+from __future__ import annotations
+
+import time
+
+
+def _format_rfc3339_microseconds(timestamp: int, /) -> str:
+    """Return an RFC 3339 formatted string representing the given timestamp.
+
+    :param timestamp: The timestamp to format, in microseconds.
+    """
+    seconds, fraction = divmod(timestamp, 10**6)
+    return time.strftime('%Y-%m-%d %H:%M:%S', time.gmtime(seconds)) + f'.{fraction // 1_000}'
diff --git a/sphinx/util/i18n.py b/sphinx/util/i18n.py
index b08ab29ff..2f2d500d9 100644
--- a/sphinx/util/i18n.py
+++ b/sphinx/util/i18n.py
@@ -15,7 +15,12 @@ from babel.messages.pofile import read_po
 from sphinx.errors import SphinxError
 from sphinx.locale import __
 from sphinx.util import logging
-from sphinx.util.osutil import SEP, canon_path, relpath
+from sphinx.util.osutil import (
+    SEP,
+    _last_modified_time,
+    canon_path,
+    relpath,
+)
 
 if TYPE_CHECKING:
     import datetime as dt
@@ -84,7 +89,7 @@ class CatalogInfo(LocaleFileInfoBase):
     def is_outdated(self) -> bool:
         return (
             not path.exists(self.mo_path) or
-            path.getmtime(self.mo_path) < path.getmtime(self.po_path))
+            _last_modified_time(self.mo_path) < _last_modified_time(self.po_path))
 
     def write_mo(self, locale: str, use_fuzzy: bool = False) -> None:
         with open(self.po_path, encoding=self.charset) as file_po:
diff --git a/sphinx/util/osutil.py b/sphinx/util/osutil.py
index 8552773f8..6c61390f1 100644
--- a/sphinx/util/osutil.py
+++ b/sphinx/util/osutil.py
@@ -16,7 +16,6 @@ from typing import TYPE_CHECKING
 from sphinx.locale import __
 
 if TYPE_CHECKING:
-    from collections.abc import Iterator
     from pathlib import Path
     from types import TracebackType
     from typing import Any
@@ -72,20 +71,25 @@ def ensuredir(file: str | os.PathLike[str]) -> None:
     os.makedirs(file, exist_ok=True)
 
 
-def mtimes_of_files(dirnames: list[str], suffix: str) -> Iterator[float]:
-    for dirname in dirnames:
-        for root, _dirs, files in os.walk(dirname):
-            for sfile in files:
-                if sfile.endswith(suffix):
-                    with contextlib.suppress(OSError):
-                        yield path.getmtime(path.join(root, sfile))
+def _last_modified_time(source: str | os.PathLike[str], /) -> int:
+    """Return the last modified time of ``filename``.
+
+    The time is returned as integer microseconds.
+    The lowest common denominator of modern file-systems seems to be
+    microsecond-level precision.
+
+    We prefer to err on the side of re-rendering a file,
+    so we round up to the nearest microsecond.
+    """
+    st = source.stat() if isinstance(source, os.DirEntry) else os.stat(source)
+    # upside-down floor division to get the ceiling
+    return -(st.st_mtime_ns // -1_000)
 
 
-def copytimes(source: str | os.PathLike[str], dest: str | os.PathLike[str]) -> None:
+def _copy_times(source: str | os.PathLike[str], dest: str | os.PathLike[str]) -> None:
     """Copy a file's modification times."""
-    st = os.stat(source)
-    if hasattr(os, 'utime'):
-        os.utime(dest, (st.st_atime, st.st_mtime))
+    st = source.stat() if isinstance(source, os.DirEntry) else os.stat(source)
+    os.utime(dest, ns=(st.st_atime_ns, st.st_mtime_ns))
 
 
 def copyfile(
@@ -128,7 +132,7 @@ def copyfile(
         shutil.copyfile(source, dest)
         with contextlib.suppress(OSError):
             # don't do full copystat because the source may be read-only
-            copytimes(source, dest)
+            _copy_times(source, dest)
 
 
 _no_fn_re = re.compile(r'[^a-zA-Z0-9_-]')
diff --git a/tests/test_extensions/test_ext_apidoc.py b/tests/test_extensions/test_ext_apidoc.py
index 13c43dfdf..0d1b519ce 100644
--- a/tests/test_extensions/test_ext_apidoc.py
+++ b/tests/test_extensions/test_ext_apidoc.py
@@ -678,7 +678,7 @@ def test_remove_old_files(tmp_path: Path):
     (gen_dir / 'other.rst').write_text('', encoding='utf8')
     apidoc_main(['-o', str(gen_dir), str(module_dir)])
     assert set(gen_dir.iterdir()) == {gen_dir / 'modules.rst', gen_dir / 'example.rst', gen_dir / 'other.rst'}
-    example_mtime = (gen_dir / 'example.rst').stat().st_mtime
+    example_mtime = (gen_dir / 'example.rst').stat().st_mtime_ns
     apidoc_main(['--remove-old', '-o', str(gen_dir), str(module_dir)])
     assert set(gen_dir.iterdir()) == {gen_dir / 'modules.rst', gen_dir / 'example.rst'}
-    assert (gen_dir / 'example.rst').stat().st_mtime == example_mtime
+    assert (gen_dir / 'example.rst').stat().st_mtime_ns == example_mtime
diff --git a/tests/test_intl/test_intl.py b/tests/test_intl/test_intl.py
index 3a6c517f9..c7653065a 100644
--- a/tests/test_intl/test_intl.py
+++ b/tests/test_intl/test_intl.py
@@ -40,7 +40,7 @@ def write_mo(pathname, po):
         return mofile.write_mo(f, po)
 
 
-def _set_mtime_ns(target, value):
+def _set_mtime_ns(target: str | os.PathLike[str], value: int) -> int:
     os.utime(target, ns=(value, value))
     return os.stat(target).st_mtime_ns
 
diff --git a/tests/test_util/test_util_docutils.py b/tests/test_util/test_util_docutils.py
index cefee412f..a5423a216 100644
--- a/tests/test_util/test_util_docutils.py
+++ b/tests/test_util/test_util_docutils.py
@@ -46,25 +46,25 @@ def test_SphinxFileOutput(tmpdir):
     filename = str(tmpdir / 'test.txt')
     output = SphinxFileOutput(destination_path=filename)
     output.write(content)
-    os.utime(filename, (0, 0))
+    os.utime(filename, ns=(0, 0))
 
     # overwrite it again
     output.write(content)
-    assert os.stat(filename).st_mtime != 0  # updated
+    assert os.stat(filename).st_mtime_ns != 0  # updated
 
     # write test2.txt at first
     filename = str(tmpdir / 'test2.txt')
     output = SphinxFileOutput(destination_path=filename, overwrite_if_changed=True)
     output.write(content)
-    os.utime(filename, (0, 0))
+    os.utime(filename, ns=(0, 0))
 
     # overwrite it again
     output.write(content)
-    assert os.stat(filename).st_mtime == 0  # not updated
+    assert os.stat(filename).st_mtime_ns == 0  # not updated
 
     # overwrite it again (content changed)
     output.write(content + "; content change")
-    assert os.stat(filename).st_mtime != 0  # updated
+    assert os.stat(filename).st_mtime_ns != 0  # updated
 
 
 def test_SphinxTranslator(app):
diff --git a/tests/test_util/test_util_i18n.py b/tests/test_util/test_util_i18n.py
index f2f324970..01d343d5f 100644
--- a/tests/test_util/test_util_i18n.py
+++ b/tests/test_util/test_util_i18n.py
@@ -38,7 +38,8 @@ def test_catalog_outdated(tmp_path):
     mo_file.write_text('#', encoding='utf8')
     assert not cat.is_outdated()  # if mo is exist and newer than po
 
-    os.utime(mo_file, (os.stat(mo_file).st_mtime - 10,) * 2)  # to be outdate
+    new_mtime = os.stat(mo_file).st_mtime_ns - 10_000_000_000
+    os.utime(mo_file, ns=(new_mtime, new_mtime))  # to be outdated
     assert cat.is_outdated()  # if mo is exist and older than po