diff --git a/burr/core/state.py b/burr/core/state.py
index f86c1c786..d5fbcc31e 100644
--- a/burr/core/state.py
+++ b/burr/core/state.py
@@ -436,8 +436,10 @@ def wipe(self, delete: Optional[list[str]] = None, keep: Optional[list[str]] = N
             )
         if delete is not None:
             fields_to_delete = delete
-        else:
+        elif keep is not None:
             fields_to_delete = [key for key in self._state if key not in keep]
+        else:
+            fields_to_delete = list(self._state)
         return self.apply_operation(DeleteField(fields_to_delete))
 
     def merge(self, other: "State") -> "State[StateType]":
diff --git a/tests/core/test_state.py b/tests/core/test_state.py
index c31a32ead..82a28678b 100644
--- a/tests/core/test_state.py
+++ b/tests/core/test_state.py
@@ -121,6 +121,13 @@ def test_state_wipe_keep():
     assert wiped.get_all() == {"foo": "bar"}
 
 
+def test_state_wipe_all():
+    # wipe() with neither delete nor keep should clear everything, as documented.
+    state = State({"foo": "bar", "baz": "qux"})
+    wiped = state.wipe()
+    assert wiped.get_all() == {}
+
+
 def test_state_append_validate_failure():
     state = State({"foo": "bar"})
     with pytest.raises(ValueError, match="non-appendable"):