diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 4d67f09bd..e006d90ac 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -51,12 +51,13 @@ jobs:
           - "3.8"
           - "3.9"
           - "3.10"
+          - "3.11"
         include:
           # On macOS don't bother with 3.8, just to get faster builds.
           - os: macos-latest
             python-version: "3.9"
           - os: macos-latest
-            python-version: "3.10"
+            python-version: "3.11"
           # We only support PyPy on Linux at the moment.
           - os: ubuntu-latest
             python-version: "pypy-3.8"
@@ -174,7 +175,7 @@ jobs:
           # 22.04 has some issue with Tor at the moment:
           # https://tahoe-lafs.org/trac/tahoe-lafs/ticket/3943
           - os: ubuntu-20.04
-            python-version: "3.9"
+            python-version: "3.11"
             force-foolscap: false
     steps:
 
diff --git a/newsfragments/3982.feature b/newsfragments/3982.feature
new file mode 100644
index 000000000..0d48fa476
--- /dev/null
+++ b/newsfragments/3982.feature
@@ -0,0 +1 @@
+Added support for Python 3.11.
\ No newline at end of file
diff --git a/setup.py b/setup.py
index 98177bd41..53fc42c62 100644
--- a/setup.py
+++ b/setup.py
@@ -55,7 +55,9 @@ install_requires = [
     # * foolscap >= 0.12.6 has an i2p.sam_endpoint() that takes kwargs
     # * foolscap 0.13.2 drops i2p support completely
     # * foolscap >= 21.7 is necessary for Python 3 with i2p support.
+    # * foolscap >= 23.3 is necessary for Python 3.11.
     "foolscap >= 21.7.0",
+    "foolscap >= 23.3.0; python_version > '3.10'",
 
     # * cryptography 2.6 introduced some ed25519 APIs we rely on.  Note that
     #   Twisted[conch] also depends on cryptography and Twisted[tls]
@@ -380,8 +382,8 @@ setup(name="tahoe-lafs", # also set in __init__.py
       package_dir = {'':'src'},
       packages=find_packages('src') + ['allmydata.test.plugins'],
       classifiers=trove_classifiers,
-      # We support Python 3.8 or later. 3.11 is not supported yet.
-      python_requires=">=3.8, <3.11",
+      # We support Python 3.8 or later, 3.12 is untested for now
+      python_requires=">=3.8, <3.12",
       install_requires=install_requires,
       extras_require={
           # Duplicate the Twisted pywin32 dependency here.  See
diff --git a/src/allmydata/test/cli/wormholetesting.py b/src/allmydata/test/cli/wormholetesting.py
index 744f9d75a..4775ca5ef 100644
--- a/src/allmydata/test/cli/wormholetesting.py
+++ b/src/allmydata/test/cli/wormholetesting.py
@@ -34,7 +34,7 @@ from __future__ import annotations
 
 from typing import Iterator, Optional, List, Tuple
 from collections.abc import Awaitable
-from inspect import getargspec
+from inspect import getfullargspec
 from itertools import count
 from sys import stderr
 
@@ -141,8 +141,8 @@ def _verify():
     """
     # Poor man's interface verification.
 
-    a = getargspec(create)
-    b = getargspec(MemoryWormholeServer.create)
+    a = getfullargspec(create)
+    b = getfullargspec(MemoryWormholeServer.create)
     # I know it has a `self` argument at the beginning.  That's okay.
     b = b._replace(args=b.args[1:])
     assert a == b, "{} != {}".format(a, b)