diff --git a/stdlib/2/__builtin__.pyi b/stdlib/2/__builtin__.pyi
index daadf8fb040c..4c94058b987d 100644
--- a/stdlib/2/__builtin__.pyi
+++ b/stdlib/2/__builtin__.pyi
@@ -183,6 +183,7 @@ class int:
     def __neg__(self) -> int: ...
     def __pos__(self) -> int: ...
     def __invert__(self) -> int: ...
+    def __trunc__(self) -> int: ...
     if sys.version_info >= (3,):
         def __round__(self, ndigits: Optional[int] = ...) -> int: ...
     def __getnewargs__(self) -> Tuple[int]: ...
@@ -240,6 +241,7 @@ class float:
     def __rdivmod__(self, x: float) -> Tuple[float, float]: ...
     def __rpow__(self, x: float) -> float: ...
     def __getnewargs__(self) -> Tuple[float]: ...
+    def __trunc__(self) -> int: ...
     if sys.version_info >= (3,):
         @overload
         def __round__(self) -> int: ...
diff --git a/stdlib/2and3/builtins.pyi b/stdlib/2and3/builtins.pyi
index daadf8fb040c..4c94058b987d 100644
--- a/stdlib/2and3/builtins.pyi
+++ b/stdlib/2and3/builtins.pyi
@@ -183,6 +183,7 @@ class int:
     def __neg__(self) -> int: ...
     def __pos__(self) -> int: ...
     def __invert__(self) -> int: ...
+    def __trunc__(self) -> int: ...
     if sys.version_info >= (3,):
         def __round__(self, ndigits: Optional[int] = ...) -> int: ...
     def __getnewargs__(self) -> Tuple[int]: ...
@@ -240,6 +241,7 @@ class float:
     def __rdivmod__(self, x: float) -> Tuple[float, float]: ...
     def __rpow__(self, x: float) -> float: ...
     def __getnewargs__(self) -> Tuple[float]: ...
+    def __trunc__(self) -> int: ...
     if sys.version_info >= (3,):
         @overload
         def __round__(self) -> int: ...