diff --git a/changelogs/fragments/fix-expect-indefinite-timeout.yml b/changelogs/fragments/fix-expect-indefinite-timeout.yml
new file mode 100644
index 00000000000..32bf6c274aa
--- /dev/null
+++ b/changelogs/fragments/fix-expect-indefinite-timeout.yml
@@ -0,0 +1,2 @@
+bugfixes:
+  - expect - fix argument spec error using timeout=null (https://github.com/ansible/ansible/issues/80982).
diff --git a/lib/ansible/modules/expect.py b/lib/ansible/modules/expect.py
index 75525fed44d..8f8355ff55f 100644
--- a/lib/ansible/modules/expect.py
+++ b/lib/ansible/modules/expect.py
@@ -42,7 +42,7 @@ options:
         responses. List functionality is new in 2.1.
     required: true
   timeout:
-    type: int
+    type: raw
     description:
       - Amount of time in seconds to wait for the expected strings. Use
         V(null) to disable timeout.
@@ -132,6 +132,7 @@ except ImportError:
 
 from ansible.module_utils.basic import AnsibleModule, missing_required_lib
 from ansible.module_utils.common.text.converters import to_bytes, to_native
+from ansible.module_utils.common.validation import check_type_int
 
 
 def response_closure(module, question, responses):
@@ -157,7 +158,7 @@ def main():
             creates=dict(type='path'),
             removes=dict(type='path'),
             responses=dict(type='dict', required=True),
-            timeout=dict(type='int', default=30),
+            timeout=dict(type='raw', default=30),
             echo=dict(type='bool', default=False),
         )
     )
@@ -172,6 +173,11 @@ def main():
     removes = module.params['removes']
     responses = module.params['responses']
     timeout = module.params['timeout']
+    if timeout is not None:
+        try:
+            timeout = check_type_int(timeout)
+        except TypeError as te:
+            module.fail_json(msg=f"argument 'timeout' is of type {type(timeout)} and we were unable to convert to int: {te}")
     echo = module.params['echo']
 
     events = dict()
diff --git a/test/integration/targets/expect/tasks/main.yml b/test/integration/targets/expect/tasks/main.yml
index d6f43f2c6ae..f7431e19d14 100644
--- a/test/integration/targets/expect/tasks/main.yml
+++ b/test/integration/targets/expect/tasks/main.yml
@@ -148,6 +148,15 @@
     - "echo_result.stdout_lines[-2] == 'foobar'"
     - "echo_result.stdout_lines[-1] == 'bar'"
 
+- name: test timeout is valid as null
+  expect:
+    command: "{{ansible_python_interpreter}} {{test_command_file}}"
+    responses:
+      foo: bar
+    echo: true
+    timeout: null  # wait indefinitely
+  timeout: 2  # but shouldn't be waiting long
+
 - name: test response list
   expect:
     command: "{{ansible_python_interpreter}} {{test_command_file}} foo foo"