diff --git a/stdlib/3/multiprocessing/connection.pyi b/stdlib/3/multiprocessing/connection.pyi
index 7627b5226..76bdca01c 100644
--- a/stdlib/3/multiprocessing/connection.pyi
+++ b/stdlib/3/multiprocessing/connection.pyi
@@ -1,15 +1,34 @@
 from typing import Any, Iterable, List, Optional, Tuple, Type, Union
 import socket
+import sys
 import types
 
 # https://docs.python.org/3/library/multiprocessing.html#address-formats
 _Address = Union[str, Tuple[str, int]]
 
-def deliver_challenge(connection: Connection, authkey: bytes) -> None: ...
-def answer_challenge(connection: Connection, authkey: bytes) -> None: ...
-def wait(object_list: Iterable[Union[Connection, socket.socket, int]], timeout: Optional[float] = ...) -> List[Union[Connection, socket.socket, int]]: ...
-def Client(address: _Address, family: Optional[str] = ..., authkey: Optional[bytes] = ...) -> Connection: ...
-def Pipe(duplex: bool = ...) -> Tuple[Connection, Connection]: ...
+class _ConnectionBase:
+    @property
+    def closed(self) -> bool: ...  # undocumented
+    @property
+    def readable(self) -> bool: ...  # undocumented
+    @property
+    def writable(self) -> bool: ...  # undocumented
+    def fileno(self) -> int: ...
+    def close(self) -> None: ...
+    def send_bytes(self,
+                   buf: bytes,
+                   offset: int = ...,
+                   size: Optional[int] = ...) -> None: ...
+    def send(self, obj: Any) -> None: ...
+    def recv_bytes(self, maxlength: Optional[int] = ...) -> bytes: ...
+    def recv_bytes_into(self, buf: Any, offset: int = ...) -> int: ...
+    def recv(self) -> Any: ...
+    def poll(self, timeout: Optional[float] = ...) -> bool: ...
+
+class Connection(_ConnectionBase): ...
+
+if sys.platform == "win32":
+    class PipeConnection(_ConnectionBase): ...
 
 class Listener:
     def __init__(self, address: Optional[_Address] = ..., family: Optional[str] = ..., backlog: int = ..., authkey: Optional[bytes] = ...) -> None: ...
@@ -22,15 +41,8 @@ class Listener:
     def __enter__(self) -> Listener: ...
     def __exit__(self, exc_type: Optional[Type[BaseException]], exc_value: Optional[BaseException], exc_tb: Optional[types.TracebackType]) -> None: ...
 
-class Connection:
-    def close(self) -> None: ...
-    def fileno(self) -> int: ...
-    def poll(self, timeout: Optional[float] = ...) -> bool: ...
-    def recv(self) -> Any: ...
-    def recv_bytes(self, maxlength: Optional[int] = ...) -> bytes: ...
-    def recv_bytes_into(self, buf: Any, offset: int = ...) -> int: ...
-    def send(self, obj: Any) -> None: ...
-    def send_bytes(self,
-                   buf: bytes,
-                   offset: int = ...,
-                   size: Optional[int] = ...) -> None: ...
+def deliver_challenge(connection: Connection, authkey: bytes) -> None: ...
+def answer_challenge(connection: Connection, authkey: bytes) -> None: ...
+def wait(object_list: Iterable[Union[Connection, socket.socket, int]], timeout: Optional[float] = ...) -> List[Union[Connection, socket.socket, int]]: ...
+def Client(address: _Address, family: Optional[str] = ..., authkey: Optional[bytes] = ...) -> Connection: ...
+def Pipe(duplex: bool = ...) -> Tuple[Connection, Connection]: ...