diff --git a/stdlib/2/os/__init__.pyi b/stdlib/2/os/__init__.pyi
index 8f7147167..4f7575d0d 100644
--- a/stdlib/2/os/__init__.pyi
+++ b/stdlib/2/os/__init__.pyi
@@ -192,19 +192,19 @@ def statvfs(path: _PathType) -> _StatVFS: ...
 def symlink(source: _PathType, link_name: _PathType) -> None: ...
 def unlink(path: _PathType) -> None: ...
 def utime(path: _PathType, times: Optional[Tuple[int, int]]) -> None: ...
-def walk(top: _PathType, topdown: bool = ..., onerror: Any = ...,
-         followlinks: bool = ...) -> Iterator[Tuple[_PathType, List[_PathType],
-                                                    List[_PathType]]]: ...
+def walk(top: AnyStr, topdown: bool = ..., onerror: Any = ...,
+         followlinks: bool = ...) -> Iterator[Tuple[AnyStr, List[AnyStr],
+                                                    List[Anystr]]]: ...
 
 def abort() -> None: ...
 def execl(file: _PathType, *args) -> None: ...
 def execle(file: _PathType, *args) -> None: ...
 def execlp(file: _PathType, *args) -> None: ...
 def execlpe(file: _PathType, *args) -> None: ...
-def execv(path: _PathType, args: Union[Tuple[_PathType], List[_PathType]]) -> None: ...
-def execve(path: _PathType, args: Union[Tuple[_PathType], List[_PathType]], env: Mapping[_PathType, _PathType]) -> None: ...
-def execvp(file: _PathType, args: Union[Tuple[_PathType], List[_PathType]]) -> None: ...
-def execvpe(file: _PathType, args: Union[Tuple[_PathType], List[_PathType]], env: Mapping[_PathType, _PathType]) -> None: ...
+def execv(path: _PathType, args: Union[Tuple[Union[bytes, Text]], List[Union[bytes, Text]]]) -> None: ...
+def execve(path: _PathType, args: Union[Tuple[Union[bytes, Text]], List[Union[bytes, Text]]], env: Mapping[str, str]) -> None: ...
+def execvp(file: _PathType, args: Union[Tuple[Union[bytes, Text]], List[Union[bytes, Text]]]) -> None: ...
+def execvpe(file: _PathType, args: Union[Tuple[Union[bytes, Text]], List[Union[bytes, Text]]], env: Mapping[str, str]) -> None: ...
 def _exit(n: int) -> NoReturn: ...
 def fork() -> int: ...
 def forkpty() -> Tuple[int, int]: ...
@@ -224,11 +224,11 @@ def spawnlp(mode: int, file: _PathType, arg0: _PathType,
             *args: _PathType) -> int: ...  # Unix only TODO
 def spawnlpe(mode: int, file: _PathType, arg0: _PathType, *args: Any) -> int:
     ...  # Imprecise signature; Unix only TODO
-def spawnv(mode: int, path: _PathType, args: List[_PathType]) -> int: ...
-def spawnve(mode: int, path: _PathType, args: List[_PathType],
+def spawnv(mode: int, path: _PathType, args: List[Union[bytes, Text]]) -> int: ...
+def spawnve(mode: int, path: _PathType, args: List[Union[bytes, Text]],
             env: Mapping[str, str]) -> int: ...
-def spawnvp(mode: int, file: _PathType, args: List[_PathType]) -> int: ...  # Unix only
-def spawnvpe(mode: int, file: _PathType, args: List[_PathType],
+def spawnvp(mode: int, file: _PathType, args: List[Union[bytes, Text]]) -> int: ...  # Unix only
+def spawnvpe(mode: int, file: _PathType, args: List[Union[bytes, Text]],
              env: Mapping[str, str]) -> int:
     ...  # Unix only
 def startfile(path: _PathType, operation: Optional[str] = ...) -> None: ...  # Windows only
diff --git a/stdlib/3/os/__init__.pyi b/stdlib/3/os/__init__.pyi
index 8e942a364..ad537c9a3 100644
--- a/stdlib/3/os/__init__.pyi
+++ b/stdlib/3/os/__init__.pyi
@@ -306,22 +306,21 @@ def unlink(path: _PathType) -> None: ...
 def utime(path: _PathType, times: Union[Tuple[int, int], Tuple[float, float]] = ...) -> None: ...
 
 # TODO onerror: function from OSError to void
-def walk(top: _PathType, topdown: bool = ..., onerror: Any = ...,
-         followlinks: bool = ...) -> Iterator[Tuple[_PathType, List[_PathType],
-                                                    List[_PathType]]]: ...
+def walk(top: AnyStr, topdown: bool = ..., onerror: Any = ...,
+         followlinks: bool = ...) -> Iterator[Tuple[AnyStr, List[AnyStr],
+                                                    List[AnyStr]]]: ...
 
 def abort() -> 'None': ...
-def execl(path: _PathType, arg0: _PathType, *args: _PathType) -> None: ...
-def execle(path: _PathType, arg0: _PathType,
+def execl(path: _PathType, arg0: Union[bytes, Text], *args: Union[bytes, Text]) -> None: ...
+def execle(path: _PathType, arg0: Union[bytes, Text],
            *args: Any) -> None: ...  # Imprecise signature
-def execlp(path: _PathType, arg0: _PathType, *args: _PathType) -> None: ...
-def execlpe(path: _PathType, arg0: _PathType,
+def execlp(path: _PathType, arg0: Union[bytes, Text], *args: Union[bytes, Text]) -> None: ...
+def execlpe(path: _PathType, arg0: Union[bytes, Text],
             *args: Any) -> None: ...  # Imprecise signature
-def execv(path: _PathType, args: Union[Tuple[_PathType], List[_PathType]]) -> None: ...
-def execve(path: _PathType, args: Union[Tuple[_PathType], List[_PathType]], env: Mapping[_PathType, _PathType]) -> None: ...
-def execvp(file: _PathType, args: Union[Tuple[_PathType], List[_PathType]]) -> None: ...
-def execvpe(file: _PathType, args: Union[Tuple[_PathType], List[_PathType]],
-            env: Mapping[str, str]) -> None: ...
+def execv(path: _PathType, args: Union[Tuple[Union[bytes, Text]], List[Union[bytes, Text]]]) -> None: ...
+def execve(path: _PathType, args: Union[Tuple[Union[bytes, Text]], List[Union[bytes, Text]]], env: Mapping[str, str]) -> None: ...
+def execvp(file: _PathType, args: Union[Tuple[Union[bytes, Text]], List[Union[bytes, Text]]]) -> None: ...
+def execvpe(file: _PathType, args: Union[Tuple[Union[bytes, Text]], List[Union[bytes, Text]]], env: Mapping[str, str]) -> None: ...
 def _exit(n: int) -> NoReturn: ...
 def fork() -> int: ...  # Unix only
 def forkpty() -> Tuple[int, int]: ...  # some flavors of Unix
@@ -343,11 +342,11 @@ def spawnlp(mode: int, file: _PathType, arg0: _PathType,
             *args: _PathType) -> int: ...  # Unix only TODO
 def spawnlpe(mode: int, file: _PathType, arg0: _PathType, *args: Any) -> int:
     ...  # Imprecise signature; Unix only TODO
-def spawnv(mode: int, path: _PathType, args: List[_PathType]) -> int: ...
-def spawnve(mode: int, path: _PathType, args: List[_PathType],
+def spawnv(mode: int, path: _PathType, args: List[Union[bytes, Text]]) -> int: ...
+def spawnve(mode: int, path: _PathType, args: List[Union[bytes, Text]],
             env: Mapping[str, str]) -> int: ...
-def spawnvp(mode: int, file: _PathType, args: List[_PathType]) -> int: ...  # Unix only
-def spawnvpe(mode: int, file: _PathType, args: List[_PathType],
+def spawnvp(mode: int, file: _PathType, args: List[Union[bytes, Text]]) -> int: ...  # Unix only
+def spawnvpe(mode: int, file: _PathType, args: List[Union[bytes, Text]],
              env: Mapping[str, str]) -> int:
     ...  # Unix only
 def startfile(path: _PathType, operation: Optional[str] = ...) -> None: ...  # Windows only