diff --git a/doc/changelog.rst b/doc/changelog.rst
index 8b2d94becd..2a99b1a701 100644
--- a/doc/changelog.rst
+++ b/doc/changelog.rst
@@ -22,10 +22,16 @@ Bug fixes
   from it. It now raises :class:`~bson.errors.InvalidId`, and
   :meth:`~bson.objectid.ObjectId.is_valid` returns ``False`` for such a string
   (`PYTHON-5873`_).
+- Fixed the type annotation of the ``let`` argument of
+  :class:`~pymongo.cursor.Cursor` and
+  :class:`~pymongo.asynchronous.cursor.AsyncCursor`. It is now
+  ``Optional[Mapping[str, Any]]`` instead of ``Optional[bool]``, matching what
+  the argument accepts at runtime (`PYTHON-6145`_).
 
 .. _PYTHON-6172: https://jira.mongodb.org/browse/PYTHON-6172
 .. _PYTHON-6149: https://jira.mongodb.org/browse/PYTHON-6149
 .. _PYTHON-5873: https://jira.mongodb.org/browse/PYTHON-5873
+.. _PYTHON-6145: https://jira.mongodb.org/browse/PYTHON-6145
 
 Changes in Version 4.19.0 (2026/10/14)
 --------------------------------------
diff --git a/pymongo/cursor_shared.py b/pymongo/cursor_shared.py
index 2b62b11f04..3a0acbe932 100644
--- a/pymongo/cursor_shared.py
+++ b/pymongo/cursor_shared.py
@@ -396,7 +396,7 @@ def __init__(
         comment: Optional[Any] = None,
         session: Optional[_AgnosticClientSession] = None,
         allow_disk_use: Optional[bool] = None,
-        let: Optional[bool] = None,
+        let: Optional[Mapping[str, Any]] = None,
     ) -> None:
         """Create a new cursor.
         Used by a collection's ``find()`` method to iterate over MongoDB query results.
diff --git a/test/test_typing.py b/test/test_typing.py
index 24ef06755f..054466e729 100644
--- a/test/test_typing.py
+++ b/test/test_typing.py
@@ -71,6 +71,7 @@ class ImplicitMovie(TypedDict):
 from pymongo.operations import DeleteOne, InsertOne, ReplaceOne
 from pymongo.read_preferences import ReadPreference
 from pymongo.synchronous.collection import Collection
+from pymongo.synchronous.cursor import Cursor
 from test import IntegrationTest, PyMongoTestCase, client_context
 
 TEST_PATH = os.path.join(os.path.dirname(os.path.realpath(__file__)), "mypy_fails")
@@ -137,6 +138,10 @@ def to_list(iterable: Iterable[dict[str, Any]]) -> list[dict[str, Any]]:
         docs = to_list(cursor)
         self.assertTrue(docs)
 
+    @only_type_check
+    def test_cursor_let(self) -> None:
+        Cursor(self.coll, let={"threshold": 1})
+
     def test_distinct(self) -> None:
         self.coll.delete_many({})
         self.coll.insert_many(