diff --git a/telethon/network/mtproto_sender.py b/telethon/network/mtproto_sender.py
index ef8b4794..674a4e03 100644
--- a/telethon/network/mtproto_sender.py
+++ b/telethon/network/mtproto_sender.py
@@ -28,8 +28,10 @@ class MtProtoSender:
         self._need_confirmation = []  # Message IDs that need confirmation
         self._pending_receive = []  # Requests sent waiting to be received
 
-        # Store an RLock instance to make this class safely multi-threaded
-        self._lock = RLock()
+        # Sending and receiving are independent, but two threads cannot
+        # send or receive at the same time no matter what.
+        self._send_lock = RLock()
+        self._recv_lock = RLock()
 
         # Used when logging out, the only request that seems to use 'ack'
         # TODO There might be a better way to handle msgs_ack requests
@@ -52,23 +54,17 @@ class MtProtoSender:
         """Sends the specified MTProtoRequest, previously sending any message
            which needed confirmation."""
 
-        # Now only us can be using this method
-        with self._lock:
-            self._logger.debug('send() acquired the lock')
+        # If any message needs confirmation send an AckRequest first
+        self._send_acknowledges()
 
-            # If any message needs confirmation send an AckRequest first
-            self._send_acknowledges()
+        # Finally send our packed request
+        with BinaryWriter() as writer:
+            request.on_send(writer)
+            self._send_packet(writer.get_bytes(), request)
+            self._pending_receive.append(request)
 
-            # Finally send our packed request
-            with BinaryWriter() as writer:
-                request.on_send(writer)
-                self._send_packet(writer.get_bytes(), request)
-                self._pending_receive.append(request)
-
-            # And update the saved session
-            self.session.save()
-
-        self._logger.debug('send() released the lock')
+        # And update the saved session
+        self.session.save()
 
     def _send_acknowledges(self):
         """Sends a messages acknowledge for all those who _need_confirmation"""
@@ -90,16 +86,13 @@ class MtProtoSender:
            Any unhandled object (likely updates) will be passed to
            update_state.process(TLObject).
         """
-        # TODO Don't ignore updates
-        self._logger.debug('Receiving a message...')
-        body = self.connection.recv()
-        message, remote_msg_id, remote_seq = self._decode_msg(body)
+        with self._recv_lock:
+            body = self.connection.recv()
 
+        message, remote_msg_id, remote_seq = self._decode_msg(body)
         with BinaryReader(message) as reader:
             self._process_msg(remote_msg_id, remote_seq, reader, update_state)
 
-        self._logger.debug('Received message.')
-
     # endregion
 
     # region Low level processing
@@ -107,8 +100,6 @@ class MtProtoSender:
     def _send_packet(self, packet, request):
         """Sends the given packet bytes with the additional
            information of the original request.
-
-           This does NOT lock the threads!
         """
         request.request_msg_id = self.session.get_new_msg_id()
 
@@ -134,7 +125,8 @@ class MtProtoSender:
                 self.session.auth_key.key_id, signed=False)
             cipher_writer.write(msg_key)
             cipher_writer.write(cipher_text)
-            self.connection.send(cipher_writer.get_bytes())
+            with self._send_lock:
+                self.connection.send(cipher_writer.get_bytes())
 
     def _decode_msg(self, body):
         """Decodes an received encrypted message body bytes"""
diff --git a/telethon/telegram_client.py b/telethon/telegram_client.py
index 3ac6e65f..17e2ccb4 100644
--- a/telethon/telegram_client.py
+++ b/telethon/telegram_client.py
@@ -2,7 +2,7 @@ import os
 import threading
 from datetime import datetime, timedelta
 from mimetypes import guess_type
-from threading import RLock, Thread
+from threading import Thread
 
 from . import TelegramBareClient
 from . import helpers as utils
@@ -50,9 +50,6 @@ class TelegramClient(TelegramBareClient):
        As opposed to the TelegramBareClient, this one  features downloading
        media from different data centers, starting a second thread to
        handle updates, and some very common functionality.
-
-       This should be used when the (slight) overhead of having locks,
-       threads, and possibly multiple connections is not an issue.
     """
 
     # region Initialization
@@ -118,9 +115,6 @@ class TelegramClient(TelegramBareClient):
             timeout=timeout
         )
 
-        # Safety across multiple threads (for the updates thread)
-        self._lock = RLock()
-
         # Used on connection - the user may modify these and reconnect
         kwargs['app_version'] = kwargs.get('app_version', self.__version__)
         for name, value in kwargs.items():
@@ -239,8 +233,6 @@ class TelegramClient(TelegramBareClient):
             raise AssertionError('Cannot invoke requests from the ReadThread')
 
         try:
-            self._lock.acquire()
-
             # Users may call this method from within some update handler.
             # If this is the case, then the thread invoking the request
             # will be the one which should be reading (but is invoking the
@@ -259,9 +251,6 @@ class TelegramClient(TelegramBareClient):
             self.reconnect(new_dc=e.new_dc)
             return self.invoke(request)
 
-        finally:
-            self._lock.release()
-
     # Let people use client(SomeRequest()) instead client.invoke(...)
     __call__ = invoke