diff --git a/Lib/subprocess.py b/Lib/subprocess.py
index 7ae8df154b481f..75fe912c330e95 100644
--- a/Lib/subprocess.py
+++ b/Lib/subprocess.py
@@ -1245,11 +1245,39 @@ def _check_timeout(self, endtime, orig_timeout, stdout_seq, stderr_seq,
         """Convenience for checking if a timeout has expired."""
         if endtime is None:
             return
+
+        def translate_newlines_partial_output(data, encoding, errors):
+            # Handle decoding the data considering it may be truncated
+            # mid-codepoint (ignore the trailing partial codepoint).
+            # See https://github.com/python/cpython/issues/87597
+            try:
+                output = self._translate_newlines(data, encoding, errors)
+            except UnicodeDecodeError as exc:
+                if exc.end == len(data):
+                    output = self._translate_newlines(data[:exc.start],
+                                                      encoding,
+                                                      errors)
+                else:
+                    raise
+            return output
+
         if skip_check_and_raise or _time() > endtime:
+            if stdout_seq is not None:
+                stdout = b''.join(stdout_seq)
+                if self.text_mode:
+                    stdout = translate_newlines_partial_output(
+                            stdout, self.stdout.encoding, self.stdout.errors)
+            else:
+                stdout = None
+            if stderr_seq is not None:
+                stderr = b''.join(stderr_seq)
+                if self.text_mode:
+                    stderr = translate_newlines_partial_output(
+                            stderr, self.stderr.encoding, self.stderr.errors)
+            else:
+                stderr = None
             raise TimeoutExpired(
-                    self.args, orig_timeout,
-                    output=b''.join(stdout_seq) if stdout_seq else None,
-                    stderr=b''.join(stderr_seq) if stderr_seq else None)
+                    self.args, orig_timeout, output=stdout, stderr=stderr)
 
 
     def wait(self, timeout=None):
diff --git a/Lib/test/test_subprocess.py b/Lib/test/test_subprocess.py
index f6854922a5b878..413f63a3c9aa31 100644
--- a/Lib/test/test_subprocess.py
+++ b/Lib/test/test_subprocess.py
@@ -1129,6 +1129,37 @@ def test_universal_newlines_communicate_encodings(self):
             stdout, stderr = popen.communicate(input='')
             self.assertEqual(stdout, '1\n2\n3\n4')
 
+    @unittest.skipIf(mswindows, "behavior currently not supported on Windows")
+    def test_universal_newlines_timeout(self):
+        with self.assertRaises(subprocess.TimeoutExpired) as c:
+            p = subprocess.run(
+                [
+                    sys.executable, "-c",
+                    "import sys, time;"
+                    r"sys.stderr.buffer.write(b'foo \xc2\xa4 bar');"
+                    "sys.stderr.buffer.flush();"
+                    r"sys.stdout.buffer.write(b'foo \xc2');"
+                    "sys.stdout.buffer.flush();"
+                    "time.sleep(10);"
+                ],
+                stdout=subprocess.PIPE,
+                stderr=subprocess.PIPE,
+                universal_newlines=True,
+                timeout=3)
+        self.assertEqual(c.exception.stdout, "foo ")
+        self.assertEqual(c.exception.stderr, "foo ¤ bar")
+
+    @unittest.skipIf(mswindows, "behavior currently not supported on Windows")
+    def test_no_output_timeout(self):
+        with self.assertRaises(subprocess.TimeoutExpired) as c:
+            p = subprocess.run(
+                [sys.executable, "-c", "import time; time.sleep(10)"],
+                stdout=subprocess.PIPE,
+                stderr=subprocess.PIPE,
+                timeout=0.1)
+        self.assertEqual(c.exception.stdout, b"")
+        self.assertEqual(c.exception.stderr, b"")
+
     def test_communicate_errors(self):
         for errors, expected in [
             ('ignore', ''),
diff --git a/Misc/NEWS.d/next/Core and Builtins/2022-08-02-18-12-34.gh-issue-87597.UHFR0H.rst b/Misc/NEWS.d/next/Core and Builtins/2022-08-02-18-12-34.gh-issue-87597.UHFR0H.rst
new file mode 100644
index 00000000000000..ff0fdb7e04f3b3
--- /dev/null
+++ b/Misc/NEWS.d/next/Core and Builtins/2022-08-02-18-12-34.gh-issue-87597.UHFR0H.rst	
@@ -0,0 +1 @@
+Store decoded output from ``subprocess.run()`` on ``TimeoutExpired`` exception when using ``text=True`` mode.