diff --git a/.github/workflows/ci-tests.yml b/.github/workflows/ci-tests.yml
index 0ee68cb..0f1bdd6 100644
--- a/.github/workflows/ci-tests.yml
+++ b/.github/workflows/ci-tests.yml
@@ -21,6 +21,7 @@ jobs:
                     - "3.9"
                     - "3.10"
                     - "3.11"
+                    - "3.12"
                     - "pypy-3.8"
                 os:
                     - "ubuntu-latest"
diff --git a/CHANGES.rst b/CHANGES.rst
index 77e6008..b5e4e04 100644
--- a/CHANGES.rst
+++ b/CHANGES.rst
@@ -1,6 +1,8 @@
 unreleased
 ==========
 
+- Add support for Python 3.12.
+
 - Fix a blocking issue when shutting down on Windows.
 
 - Fix a broken socket that sometimes occurs when reloading due to sockets being
diff --git a/setup.cfg b/setup.cfg
index 0bec643..3914d04 100644
--- a/setup.cfg
+++ b/setup.cfg
@@ -33,6 +33,7 @@ classifiers =
     Programming Language :: Python :: 3.9
     Programming Language :: Python :: 3.10
     Programming Language :: Python :: 3.11
+    Programming Language :: Python :: 3.12
     Programming Language :: Python :: Implementation :: CPython
     Programming Language :: Python :: Implementation :: PyPy
 
diff --git a/src/hupper/ipc.py b/src/hupper/ipc.py
index 1f07dc9..ec2767e 100644
--- a/src/hupper/ipc.py
+++ b/src/hupper/ipc.py
@@ -112,6 +112,10 @@ class Connection(object):
 
     _packet_len = struct.Struct('Q')
 
+    send_lock = None
+    reader_thread = None
+    on_recv = lambda _: None
+
     def __init__(self, r_fd, w_fd):
         self.r_fd = r_fd
         self.w_fd = w_fd
@@ -142,6 +146,8 @@ def close(self):
 
         close_fd(w_fd)
         close_fd(r_fd)
+        if self.reader_thread:
+            self.reader_thread.join()
 
     def _recv_packet(self):
         buf = io.BytesIO()
diff --git a/src/hupper/watchman.py b/src/hupper/watchman.py
index a164574..8ed461b 100644
--- a/src/hupper/watchman.py
+++ b/src/hupper/watchman.py
@@ -79,6 +79,10 @@ def join(self):
         finally:
             self._close_sock()
 
+    def stop(self):
+        self.enabled = False
+        self._close_sock()
+
     def run(self):
         while self.enabled:
             try:
@@ -138,10 +142,6 @@ def _is_unilateral(self, result):
                 return True
         return False
 
-    def stop(self):
-        self.enabled = False
-        self._close_sock()
-
     def _close_sock(self):
         if self._sock:
             try:
@@ -194,7 +194,8 @@ def _readline(self):
             b = self._sock.recv(4096)
             if not b:
                 self.logger.error(
-                    'Lost connection to watchman. No longer watching for changes.'
+                    'Lost connection to watchman. No longer watching for'
+                    ' changes.'
                 )
                 self.stop()
                 raise socket.timeout
diff --git a/tests/test_ipc.py b/tests/test_ipc.py
index 76d559c..9b33f51 100644
--- a/tests/test_ipc.py
+++ b/tests/test_ipc.py
@@ -11,7 +11,6 @@ def echo(pipe):
         pipe.send(msg)
         msg = q.get()
     pipe.close()
-    pipe.reader_thread.join()
 
 
 def test_ipc_close():
@@ -31,6 +30,5 @@ def test_ipc_close():
             assert c1_q.get() == "hello world"
 
             c1.close()
-            c1.reader_thread.join()
         finally:
             proc.terminate()
diff --git a/tox.ini b/tox.ini
index 833e93d..538a6ad 100644
--- a/tox.ini
+++ b/tox.ini
@@ -1,7 +1,7 @@
 [tox]
 envlist =
     lint,
-    py37,py38,py39,py310,py311,pypy3,
+    py37,py38,py39,py310,py311,py312,pypy3,
     docs,coverage
 
 isolated_build = true