diff --git a/.github/workflows/test.yml b/.github/workflows/test.yml
index dced168f..942a5e28 100644
--- a/.github/workflows/test.yml
+++ b/.github/workflows/test.yml
@@ -28,6 +28,9 @@ jobs:
           - name: py312
             python: "3.12"
             toxenv: py312
+          - name: py313
+            python: "3.13"
+            toxenv: py313
           - name: black
             python: "3.12"
             toxenv: black
diff --git a/docs/changelog.md b/docs/changelog.md
index 0bc997b9..7b7ce033 100644
--- a/docs/changelog.md
+++ b/docs/changelog.md
@@ -2,6 +2,7 @@
 
 ## Unreleased
 
+- Add support for Python 3.13 (#824)
 - Drop support for Python 3.8 (#820)
 - Flag invalid regexes in arguments to functions like
   `re.search` (#816)
diff --git a/pyanalyze/name_check_visitor.py b/pyanalyze/name_check_visitor.py
index c56c5527..2ca5521e 100644
--- a/pyanalyze/name_check_visitor.py
+++ b/pyanalyze/name_check_visitor.py
@@ -4816,8 +4816,8 @@ def visit_TypeVar(self, node: ast.TypeVar) -> Value:
                 else:
                     bound = self.visit(node.bound)
             if sys.version_info >= (3, 13):
-                if node.default is not None:
-                    default = self.visit(node.default)
+                if node.default_value is not None:
+                    default = self.visit(node.default_value)
             tv = TypeVar(node.name)
             typevar = TypeVarValue(
                 tv,
diff --git a/pyanalyze/test_arg_spec.py b/pyanalyze/test_arg_spec.py
index 7abf0bd1..2a2d2980 100644
--- a/pyanalyze/test_arg_spec.py
+++ b/pyanalyze/test_arg_spec.py
@@ -210,10 +210,19 @@ def test_get_argspec():
             Composite(KnownValue(ClassWithCall)),
         ) == asc.get_argspec(ClassWithCall.pure_async_classmethod)
 
+        # This behaves differently in 3.9 through 3.12 than in earlier and later
+        # versions. The behavior change was made in
+        # https://github.com/python/cpython/issues/63272
+        # and undone in https://github.com/python/cpython/issues/89519
+        if hasattr(ClassWithCall.classmethod_before_async, "decorator"):
+            callable = ClassWithCall.classmethod_before_async.decorator.fn
+        else:
+            callable = ClassWithCall.classmethod_before_async.__func__.fn
+
         assert BoundMethodSignature(
             Signature.make(
                 [SigParameter("cls"), SigParameter("ac")],
-                callable=ClassWithCall.classmethod_before_async.decorator.fn,
+                callable=callable,
                 is_asynq=True,
             ),
             Composite(KnownValue(ClassWithCall)),
diff --git a/setup.py b/setup.py
index a11d085c..8d56be22 100644
--- a/setup.py
+++ b/setup.py
@@ -25,6 +25,7 @@
             "Programming Language :: Python :: 3.10",
             "Programming Language :: Python :: 3.11",
             "Programming Language :: Python :: 3.12",
+            "Programming Language :: Python :: 3.13",
         ],
         keywords="quora static analysis",
         packages=["pyanalyze"],
diff --git a/tox.ini b/tox.ini
index c1b507aa..0dc8a64a 100644
--- a/tox.ini
+++ b/tox.ini
@@ -19,7 +19,7 @@ commands =
 
 [testenv:ruff]
 deps =
-    ruff==0.2.2
+    ruff==0.6.9
 
 commands =
     ruff check pyanalyze/