diff --git a/Lib/test/libregrtest/tsan.py b/Lib/test/libregrtest/tsan.py
index f1f8c8bde920ae..b41bea996638f3 100644
--- a/Lib/test/libregrtest/tsan.py
+++ b/Lib/test/libregrtest/tsan.py
@@ -36,6 +36,7 @@
 # the regression test runner with the `--parallel-threads` option enabled.
 TSAN_PARALLEL_TESTS = [
     'test_abc',
+    'test_exceptions',
     'test_hashlib',
 ]
 
diff --git a/Lib/test/support/__init__.py b/Lib/test/support/__init__.py
index 0a50912ff0ea8c..c1a00dd09e4a43 100644
--- a/Lib/test/support/__init__.py
+++ b/Lib/test/support/__init__.py
@@ -2923,7 +2923,7 @@ def force_colorized(func):
     def wrapper(*args, **kwargs):
         with force_color(True):
             return func(*args, **kwargs)
-    return wrapper
+    return thread_unsafe(wrapper)  # modifying the environment is thread-unsafe
 
 
 def force_not_colorized(func):
diff --git a/Lib/test/test_exceptions.py b/Lib/test/test_exceptions.py
index 6f212d2f91efb1..84588701e528a7 100644
--- a/Lib/test/test_exceptions.py
+++ b/Lib/test/test_exceptions.py
@@ -60,6 +60,7 @@ def raise_catch(self, exc, excname):
             self.assertEqual(buf1, buf2)
             self.assertEqual(exc.__name__, excname)
 
+    @support.thread_unsafe("TESTFN")
     def testRaising(self):
         self.raise_catch(AttributeError, "AttributeError")
         self.assertRaises(AttributeError, getattr, sys, "undefined_attribute")
@@ -1411,6 +1412,7 @@ def __str__(self):
             self.assertRaises(TypeError, str, exc)
 
     @no_tracing
+    @support.thread_unsafe("captures stderr")
     def test_badisinstance(self):
         # Bug #2542: if issubclass(e, MyException) raises an exception,
         # it should be ignored
@@ -1536,6 +1538,7 @@ def test_recursion_normalizing_infinite_exception(self):
         self.assertIn(b'Done.', out)
 
 
+    @support.thread_unsafe("uses sys.setrecursionlimit")
     @support.skip_emscripten_stack_overflow()
     def test_recursion_in_except_handler(self):
 
@@ -1672,6 +1675,7 @@ class C(object):
 
     @cpython_only
     @unittest.skipIf(_testcapi is None, "requires _testcapi")
+    @support.thread_unsafe("gc_collect()")
     def test_memory_error_cleanup(self):
         # Issue #5437: preallocated MemoryError instances should not keep
         # traceback objects alive.
@@ -1721,6 +1725,7 @@ def test_errno_ENOTDIR(self):
             os.listdir(__file__)
         self.assertEqual(cm.exception.errno, errno.ENOTDIR, cm.exception)
 
+    @support.thread_unsafe("uses catch_unraisable_exception")
     def test_unraisable(self):
         # Issue #22836: PyErr_WriteUnraisable() should give sensible reports
         class BrokenDel:
@@ -1740,6 +1745,7 @@ def __del__(self):
                              f"deallocator {obj_repr}")
             self.assertIsNotNone(cm.unraisable.exc_traceback)
 
+    @support.thread_unsafe("captures stderr")
     def test_unhandled(self):
         # Check for sensible reporting of unhandled exceptions
         for exc_type in (ValueError, BrokenStrException):
@@ -1839,6 +1845,7 @@ def g():
                 next(i)
 
     @unittest.skipUnless(__debug__, "Won't work if __debug__ is False")
+    @support.thread_unsafe("modifies global AssertionError")
     def test_assert_shadowing(self):
         # Shadowing AssertionError would cause the assert statement to
         # misbehave.
@@ -1963,6 +1970,7 @@ def test_name_error_has_name(self):
         except NameError as exc:
             self.assertEqual("bluch", exc.name)
 
+    @support.thread_unsafe("captures stderr")
     def test_issue45826(self):
         # regression test for bpo-45826
         def f():
@@ -1979,6 +1987,7 @@ def f():
 
         self.assertIn("aab", err.getvalue())
 
+    @support.thread_unsafe("captures stderr")
     def test_issue45826_focused(self):
         def f():
             try:
@@ -2099,6 +2108,7 @@ def test_reset_attributes(self):
         self.assertEqual(exc.name, None)
         self.assertEqual(exc.path, None)
 
+    @support.thread_unsafe("check_warnings")
     def test_non_str_argument(self):
         # Issue #15778
         with check_warnings(('', BytesWarning), quiet=True):
@@ -2425,6 +2435,7 @@ class MySyntaxError(SyntaxError):
      ^^^^^
 """, err.getvalue())
 
+    @support.thread_unsafe("TESTFN")
     def test_encodings(self):
         self.addCleanup(unlink, TESTFN)
         source = (