diff --git a/synapse/util/__init__.py b/synapse/util/__init__.py
index 9f3b8741c1db..8d9df352b25f 100644
--- a/synapse/util/__init__.py
+++ b/synapse/util/__init__.py
@@ -93,7 +93,7 @@ class Clock:
 
     _reactor: IReactorTime = attr.ib()
 
-    @defer.inlineCallbacks  # type: ignore[arg-type]  # Issue in Twisted's type annotations
+    @defer.inlineCallbacks
     def sleep(self, seconds: float) -> "Generator[Deferred[float], Any, Any]":
         d: defer.Deferred[float] = defer.Deferred()
         with context.PreserveLoggingContext():
diff --git a/tests/http/__init__.py b/tests/http/__init__.py
index d5306e7ee022..9108a3007b90 100644
--- a/tests/http/__init__.py
+++ b/tests/http/__init__.py
@@ -182,7 +182,7 @@ def wrap_server_factory_for_tls(
         )
     else:
         return TLSMemoryBIOFactory(
-            connection_creator, isClient=False, wrappedFactory=factory, clock=clock  # type: ignore[call-arg]
+            connection_creator, isClient=False, wrappedFactory=factory, clock=clock
         )
 
 
diff --git a/tests/server.py b/tests/server.py
index cfb0fb823b07..c8342db399ab 100644
--- a/tests/server.py
+++ b/tests/server.py
@@ -484,7 +484,7 @@ def getHostByName(
         if twisted.version > Version("Twisted", 23, 8, 0):
             from twisted.protocols import tls
 
-            tls._get_default_clock = lambda: self  # type: ignore[attr-defined]
+            tls._get_default_clock = lambda: self
 
         self.nameResolver = SimpleResolverComplexifier(FakeResolver())
         super().__init__()