diff --git a/pandas/_libs/lib.pyi b/pandas/_libs/lib.pyi
index 15bd5a7379105..33f6f16381639 100644
--- a/pandas/_libs/lib.pyi
+++ b/pandas/_libs/lib.pyi
@@ -63,7 +63,11 @@ def is_string_array(values: np.ndarray, skipna: bool = ...): ...
 def is_float_array(values: np.ndarray, skipna: bool = ...): ...
 def is_integer_array(values: np.ndarray, skipna: bool = ...): ...
 def is_bool_array(values: np.ndarray, skipna: bool = ...): ...
-def fast_multiget(mapping: dict, keys: np.ndarray, default=...) -> np.ndarray: ...
+def fast_multiget(
+    mapping: dict,
+    keys: np.ndarray,  # object[:]
+    default=...,
+) -> np.ndarray: ...
 def fast_unique_multiple_list_gen(gen: Generator, sort: bool = ...) -> list: ...
 def fast_unique_multiple_list(lists: list, sort: bool | None = ...) -> list: ...
 def map_infer(
diff --git a/pandas/_libs/lib.pyx b/pandas/_libs/lib.pyx
index 7ec70c8700a0a..50ea5f6d3f699 100644
--- a/pandas/_libs/lib.pyx
+++ b/pandas/_libs/lib.pyx
@@ -3088,7 +3088,7 @@ def to_object_array_tuples(rows: object) -> np.ndarray:
 
 @cython.wraparound(False)
 @cython.boundscheck(False)
-def fast_multiget(dict mapping, ndarray keys, default=np.nan) -> np.ndarray:
+def fast_multiget(dict mapping, object[:] keys, default=np.nan) -> np.ndarray:
     cdef:
         Py_ssize_t i, n = len(keys)
         object val