diff --git a/setup.cfg b/setup.cfg
index a5ffd2f3f..60731300c 100644
--- a/setup.cfg
+++ b/setup.cfg
@@ -26,7 +26,8 @@ files =
     uvicorn/_handlers,
     uvicorn/__init__.py,
     uvicorn/__main__.py,
-    uvicorn/subprocess.py
+    uvicorn/subprocess.py,
+    uvicorn/supervisors/multiprocess.py
 
 
 [mypy-tests.*]
diff --git a/uvicorn/supervisors/multiprocess.py b/uvicorn/supervisors/multiprocess.py
index 94f7238d3..c02639ac0 100644
--- a/uvicorn/supervisors/multiprocess.py
+++ b/uvicorn/supervisors/multiprocess.py
@@ -2,9 +2,14 @@
 import os
 import signal
 import threading
+from multiprocessing.context import SpawnProcess
+from socket import socket
+from types import FrameType
+from typing import Callable, List, Optional
 
 import click
 
+from uvicorn.config import Config
 from uvicorn.subprocess import get_subprocess
 
 HANDLED_SIGNALS = (
@@ -16,26 +21,31 @@
 
 
 class Multiprocess:
-    def __init__(self, config, target, sockets):
+    def __init__(
+        self,
+        config: Config,
+        target: Callable[[Optional[List[socket]]], None],
+        sockets: List[socket],
+    ) -> None:
         self.config = config
         self.target = target
         self.sockets = sockets
-        self.processes = []
+        self.processes: List[SpawnProcess] = []
         self.should_exit = threading.Event()
         self.pid = os.getpid()
 
-    def signal_handler(self, sig, frame):
+    def signal_handler(self, sig: signal.Signals, frame: FrameType) -> None:
         """
         A signal handler that is registered with the parent process.
         """
         self.should_exit.set()
 
-    def run(self):
+    def run(self) -> None:
         self.startup()
         self.should_exit.wait()
         self.shutdown()
 
-    def startup(self):
+    def startup(self) -> None:
         message = "Started parent process [{}]".format(str(self.pid))
         color_message = "Started parent process [{}]".format(
             click.style(str(self.pid), fg="cyan", bold=True)
@@ -52,7 +62,7 @@ def startup(self):
             process.start()
             self.processes.append(process)
 
-    def shutdown(self):
+    def shutdown(self) -> None:
         for process in self.processes:
             process.join()