diff --git a/stdlib/2and3/_bisect.pyi b/stdlib/2and3/_bisect.pyi
index 62335472f..38e7a7b37 100644
--- a/stdlib/2and3/_bisect.pyi
+++ b/stdlib/2and3/_bisect.pyi
@@ -1,11 +1,11 @@
 """Stub file for the '_bisect' module."""
 
-from typing import Sequence, TypeVar
+from typing import Sequence, MutableSequence, TypeVar
 
 _T = TypeVar('_T')
 def bisect(a: Sequence[_T], x: _T, lo: int = ..., hi: int = ...) -> int: ...
 def bisect_left(a: Sequence[_T], x: _T, lo: int = ..., hi: int = ...) -> int: ...
 def bisect_right(a: Sequence[_T], x: _T, lo: int = ..., hi: int = ...) -> int: ...
-def insort(a: Sequence[_T], x: _T, lo: int = ..., hi: int = ...) -> None: ...
-def insort_left(a: Sequence[_T], x: _T, lo: int = ..., hi: int = ...) -> None: ...
-def insort_right(a: Sequence[_T], x: _T, lo: int = ..., hi: int = ...) -> None: ...
+def insort(a: MutableSequence[_T], x: _T, lo: int = ..., hi: int = ...) -> None: ...
+def insort_left(a: MutableSequence[_T], x: _T, lo: int = ..., hi: int = ...) -> None: ...
+def insort_right(a: MutableSequence[_T], x: _T, lo: int = ..., hi: int = ...) -> None: ...
diff --git a/stdlib/2and3/bisect.pyi b/stdlib/2and3/bisect.pyi
index 5c541124a..04229284f 100644
--- a/stdlib/2and3/bisect.pyi
+++ b/stdlib/2and3/bisect.pyi
@@ -1,6 +1,6 @@
 # Stubs for bisect
 
-from typing import Any, Sequence, TypeVar
+from typing import Any, Sequence, MutableSequence, TypeVar
 
 _T = TypeVar('_T')
 
@@ -9,14 +9,14 @@ _T = TypeVar('_T')
 # def bisect_right(a: Sequence[_T], x: _T, lo: int = ..., hi: int = ...) -> int: ...
 # def bisect(a: Sequence[_T], x: _T, lo: int = ..., hi: int = ...) -> int: ...
 #
-# def insort_left(a: Sequence[_T], x: _T, lo: int = ..., hi: int = ...) -> int: ...
-# def insort_right(a: Sequence[_T], x: _T, lo: int = ..., hi: int = ...) -> int: ...
-# def insort(a: Sequence[_T], x: _T, lo: int = ..., hi: int = ...) -> int: ...
+# def insort_left(a: MutableSequence[_T], x: _T, lo: int = ..., hi: int = ...) -> int: ...
+# def insort_right(a: MutableSequence[_T], x: _T, lo: int = ..., hi: int = ...) -> int: ...
+# def insort(a: MutableSequence[_T], x: _T, lo: int = ..., hi: int = ...) -> int: ...
 
 def bisect_left(a: Sequence, x: Any, lo: int = ..., hi: int = ...) -> int: ...
 def bisect_right(a: Sequence, x: Any, lo: int = ..., hi: int = ...) -> int: ...
 def bisect(a: Sequence, x: Any, lo: int = ..., hi: int = ...) -> int: ...
 
-def insort_left(a: Sequence, x: Any, lo: int = ..., hi: int = ...) -> int: ...
-def insort_right(a: Sequence, x: Any, lo: int = ..., hi: int = ...) -> int: ...
-def insort(a: Sequence, x: Any, lo: int = ..., hi: int = ...) -> int: ...
+def insort_left(a: MutableSequence, x: Any, lo: int = ..., hi: int = ...) -> int: ...
+def insort_right(a: MutableSequence, x: Any, lo: int = ..., hi: int = ...) -> int: ...
+def insort(a: MutableSequence, x: Any, lo: int = ..., hi: int = ...) -> int: ...