diff --git a/NEWS b/NEWS
index 6e3865c9..74a2b173 100644
--- a/NEWS
+++ b/NEWS
@@ -3,6 +3,27 @@ testtools NEWS
 
 Changes and improvements to testtools_, grouped by release.
 
+NEXT
+~~~~
+
+2.8.6
+~~~~~
+
+Improvements
+------------
+* Improve the type annotations for ``testtools.testcase.TestCase.assertRaises``.
+  This method will now be typed correctly when called as a method or as a
+  context manager.
+  (Stephen Finucane, #577, #578)
+
+2.8.5
+~~~~~
+
+Improvements
+------------
+* Fix the type annotations for ``testtools.testcase.TestCase.useFixture``
+  (Stephen Finucane, #574)
+
 2.8.4
 ~~~~~
 
@@ -70,8 +91,7 @@ Improvements
   (Jelmer Vernooij, #538)
 
 * Allow stream=None to be passed to various TestResult
-  classes that now support verbosity; fixes a regression
-from 2.8.0.
+  classes that now support verbosity; fixes a regression from 2.8.0.
   (Jelmer Vernooij)
 
 2.8.1
diff --git a/testtools/testcase.py b/testtools/testcase.py
index e07d1ecb..d3929a97 100644
--- a/testtools/testcase.py
+++ b/testtools/testcase.py
@@ -23,7 +23,7 @@
 import types
 import unittest
 from collections.abc import Callable, Iterator
-from typing import TypeVar, cast
+from typing import TYPE_CHECKING, ParamSpec, TypeVar, cast, overload
 from unittest.case import SkipTest
 
 T = TypeVar("T")
@@ -56,6 +56,12 @@
     TestResult,
 )
 
+if TYPE_CHECKING:
+    if sys.version_info >= (3, 11):
+        from typing import Self
+    else:
+        from typing_extensions import Self
+
 # Circular import: fixtures imports gather_details from here, we import
 # fixtures, leading to gather_details not being available and fixtures being
 # unable to import it.
@@ -82,6 +88,8 @@ class _ExpectedFailure(Exception):
 
 
 # TypeVar for decorators
+_P = ParamSpec("_P")
+_R = TypeVar("_R")
 _F = TypeVar("_F", bound=Callable[..., object])
 
 
@@ -384,10 +392,10 @@ def _formatTypes(
 
     def addCleanup(
         self,
-        function: Callable[..., object],
+        function: Callable[_P, _R],
         /,
-        *arguments: object,
-        **keywordArguments: object,
+        *args: _P.args,
+        **kwargs: _P.kwargs,
     ) -> None:
         """Add a cleanup function to be called after tearDown.
 
@@ -401,7 +409,7 @@ def addCleanup(
         Cleanup functions are always called before a test finishes running,
         even if setUp is aborted by an exception.
         """
-        self._cleanups.append((function, arguments, keywordArguments))
+        self._cleanups.append((function, args, kwargs))
 
     def addOnException(self, handler: "Callable[[ExcInfo], None]") -> None:
         """Add a handler to be called when an exception occurs in test code.
@@ -493,12 +501,28 @@ def assertIsInstance(  # type: ignore[override]
             matcher = IsInstance(klass)
         self.assertThat(obj, matcher, msg or "")
 
+    @overload  # type: ignore[override]
+    def assertRaises(
+        self,
+        expected_exception: type[BaseException] | tuple[type[BaseException]],
+        callable: Callable[_P, _R],
+        *args: _P.args,
+        **kwargs: _P.kwargs,
+    ) -> BaseException: ...
+
+    @overload  # type: ignore[override]
+    def assertRaises(
+        self,
+        expected_exception: type[BaseException] | tuple[type[BaseException]],
+        callable: None = ...,
+    ) -> "_AssertRaisesContext": ...
+
     def assertRaises(  # type: ignore[override]
         self,
-        expected_exception: type[BaseException],
-        callable: Callable[..., object] | None = None,
-        *args: object,
-        **kwargs: object,
+        expected_exception: type[BaseException] | tuple[type[BaseException]],
+        callable: Callable[_P, _R] | None = None,
+        *args: _P.args,
+        **kwargs: _P.kwargs,
     ) -> "_AssertRaisesContext | BaseException":
         """Fail unless an exception of class expected_exception is thrown
         by callable when invoked with arguments args and keyword
@@ -654,9 +678,9 @@ def defaultTestResult(self) -> TestResult:
     def expectFailure(
         self,
         reason: str,
-        predicate: Callable[..., object],
-        *args: object,
-        **kwargs: object,
+        predicate: Callable[_P, _R],
+        *args: _P.args,
+        **kwargs: _P.kwargs,
     ) -> None:
         """Check that a test fails in a particular way.
 
@@ -1206,7 +1230,10 @@ class _AssertRaisesContext:
     """
 
     def __init__(
-        self, expected: type[BaseException], test_case: TestCase, msg: str | None = None
+        self,
+        expected: type[BaseException] | tuple[type[BaseException]],
+        test_case: TestCase,
+        msg: str | None = None,
     ) -> None:
         """Construct an `_AssertRaisesContext`.
 
@@ -1219,7 +1246,7 @@ def __init__(
         self.msg = msg
         self.exception: BaseException | None = None
 
-    def __enter__(self) -> "_AssertRaisesContext":
+    def __enter__(self) -> "Self":
         return self
 
     def __exit__(
@@ -1322,7 +1349,10 @@ class Nullary:
     """
 
     def __init__(
-        self, callable_object: Callable[..., object], *args: object, **kwargs: object
+        self,
+        callable_object: Callable[_P, _R],
+        *args: _P.args,
+        **kwargs: _P.kwargs,
     ) -> None:
         self._callable_object = callable_object
         self._args = args