diff --git a/libp2p/stream_muxer/mplex/mplex_stream.py b/libp2p/stream_muxer/mplex/mplex_stream.py
index 3b640df1..77546036 100644
--- a/libp2p/stream_muxer/mplex/mplex_stream.py
+++ b/libp2p/stream_muxer/mplex/mplex_stream.py
@@ -1,3 +1,5 @@
+from collections.abc import AsyncGenerator
+from contextlib import asynccontextmanager
 from types import (
     TracebackType,
 )
@@ -32,6 +34,72 @@ if TYPE_CHECKING:
     )
 
 
+class ReadWriteLock:
+    """
+    A read-write lock that allows multiple concurrent readers
+    or one exclusive writer, implemented using Trio primitives.
+    """
+
+    def __init__(self) -> None:
+        self._readers = 0
+        self._readers_lock = trio.Lock()  # Protects access to _readers count
+        self._writer_lock = trio.Semaphore(1)  # Allows only one writer at a time
+
+    async def acquire_read(self) -> None:
+        """Acquire a read lock. Multiple readers can hold it simultaneously."""
+        try:
+            async with self._readers_lock:
+                if self._readers == 0:
+                    await self._writer_lock.acquire()
+                self._readers += 1
+        except trio.Cancelled:
+            raise
+
+    async def release_read(self) -> None:
+        """Release a read lock."""
+        async with self._readers_lock:
+            if self._readers == 1:
+                self._writer_lock.release()
+            self._readers -= 1
+
+    async def acquire_write(self) -> None:
+        """Acquire an exclusive write lock."""
+        try:
+            await self._writer_lock.acquire()
+        except trio.Cancelled:
+            raise
+
+    def release_write(self) -> None:
+        """Release the exclusive write lock."""
+        self._writer_lock.release()
+
+    @asynccontextmanager
+    async def read_lock(self) -> AsyncGenerator[None, None]:
+        """Context manager for acquiring and releasing a read lock safely."""
+        acquire = False
+        try:
+            await self.acquire_read()
+            acquire = True
+            yield
+        finally:
+            if acquire:
+                with trio.CancelScope() as scope:
+                    scope.shield = True
+                    await self.release_read()
+
+    @asynccontextmanager
+    async def write_lock(self) -> AsyncGenerator[None, None]:
+        """Context manager for acquiring and releasing a write lock safely."""
+        acquire = False
+        try:
+            await self.acquire_write()
+            acquire = True
+            yield
+        finally:
+            if acquire:
+                self.release_write()
+
+
 class MplexStream(IMuxedStream):
     """
     reference: https://github.com/libp2p/go-mplex/blob/master/stream.go
@@ -46,7 +114,7 @@ class MplexStream(IMuxedStream):
     read_deadline: int | None
     write_deadline: int | None
 
-    # TODO: Add lock for read/write to avoid interleaving receiving messages?
+    rw_lock: ReadWriteLock
     close_lock: trio.Lock
 
     # NOTE: `dataIn` is size of 8 in Go implementation.
@@ -80,6 +148,7 @@ class MplexStream(IMuxedStream):
         self.event_remote_closed = trio.Event()
         self.event_reset = trio.Event()
         self.close_lock = trio.Lock()
+        self.rw_lock = ReadWriteLock()
         self.incoming_data_channel = incoming_data_channel
         self._buf = bytearray()
 
@@ -113,48 +182,49 @@ class MplexStream(IMuxedStream):
         :param n: number of bytes to read
         :return: bytes actually read
         """
-        if n is not None and n < 0:
-            raise ValueError(
-                "the number of bytes to read `n` must be non-negative or "
-                f"`None` to indicate read until EOF, got n={n}"
-            )
-        if self.event_reset.is_set():
-            raise MplexStreamReset
-        if n is None:
-            return await self._read_until_eof()
-        if len(self._buf) == 0:
-            data: bytes
-            # Peek whether there is data available. If yes, we just read until there is
-            # no data, then return.
-            try:
-                data = self.incoming_data_channel.receive_nowait()
-                self._buf.extend(data)
-            except trio.EndOfChannel:
-                raise MplexStreamEOF
-            except trio.WouldBlock:
-                # We know `receive` will be blocked here. Wait for data here with
-                # `receive` and catch all kinds of errors here.
+        async with self.rw_lock.read_lock():
+            if n is not None and n < 0:
+                raise ValueError(
+                    "the number of bytes to read `n` must be non-negative or "
+                    f"`None` to indicate read until EOF, got n={n}"
+                )
+            if self.event_reset.is_set():
+                raise MplexStreamReset
+            if n is None:
+                return await self._read_until_eof()
+            if len(self._buf) == 0:
+                data: bytes
+                # Peek whether there is data available. If yes, we just read until
+                # there is no data, then return.
                 try:
-                    data = await self.incoming_data_channel.receive()
+                    data = self.incoming_data_channel.receive_nowait()
                     self._buf.extend(data)
                 except trio.EndOfChannel:
-                    if self.event_reset.is_set():
-                        raise MplexStreamReset
-                    if self.event_remote_closed.is_set():
-                        raise MplexStreamEOF
-                except trio.ClosedResourceError as error:
-                    # Probably `incoming_data_channel` is closed in `reset` when we are
-                    # waiting for `receive`.
-                    if self.event_reset.is_set():
-                        raise MplexStreamReset
-                    raise Exception(
-                        "`incoming_data_channel` is closed but stream is not reset. "
-                        "This should never happen."
-                    ) from error
-        self._buf.extend(self._read_return_when_blocked())
-        payload = self._buf[:n]
-        self._buf = self._buf[len(payload) :]
-        return bytes(payload)
+                    raise MplexStreamEOF
+                except trio.WouldBlock:
+                    # We know `receive` will be blocked here. Wait for data here with
+                    # `receive` and catch all kinds of errors here.
+                    try:
+                        data = await self.incoming_data_channel.receive()
+                        self._buf.extend(data)
+                    except trio.EndOfChannel:
+                        if self.event_reset.is_set():
+                            raise MplexStreamReset
+                        if self.event_remote_closed.is_set():
+                            raise MplexStreamEOF
+                    except trio.ClosedResourceError as error:
+                        # Probably `incoming_data_channel` is closed in `reset` when
+                        # we are waiting for `receive`.
+                        if self.event_reset.is_set():
+                            raise MplexStreamReset
+                        raise Exception(
+                            "`incoming_data_channel` is closed but stream is not reset."
+                            "This should never happen."
+                        ) from error
+            self._buf.extend(self._read_return_when_blocked())
+            payload = self._buf[:n]
+            self._buf = self._buf[len(payload) :]
+            return bytes(payload)
 
     async def write(self, data: bytes) -> None:
         """
@@ -162,14 +232,15 @@ class MplexStream(IMuxedStream):
 
         :return: number of bytes written
         """
-        if self.event_local_closed.is_set():
-            raise MplexStreamClosed(f"cannot write to closed stream: data={data!r}")
-        flag = (
-            HeaderTags.MessageInitiator
-            if self.is_initiator
-            else HeaderTags.MessageReceiver
-        )
-        await self.muxed_conn.send_message(flag, data, self.stream_id)
+        async with self.rw_lock.write_lock():
+            if self.event_local_closed.is_set():
+                raise MplexStreamClosed(f"cannot write to closed stream: data={data!r}")
+            flag = (
+                HeaderTags.MessageInitiator
+                if self.is_initiator
+                else HeaderTags.MessageReceiver
+            )
+            await self.muxed_conn.send_message(flag, data, self.stream_id)
 
     async def close(self) -> None:
         """
diff --git a/newsfragments/748.feature.rst b/newsfragments/748.feature.rst
new file mode 100644
index 00000000..199e5b3b
--- /dev/null
+++ b/newsfragments/748.feature.rst
@@ -0,0 +1 @@
+ Add lock for read/write to avoid interleaving receiving messages in mplex_stream.py
diff --git a/tests/core/stream_muxer/test_read_write_lock.py b/tests/core/stream_muxer/test_read_write_lock.py
new file mode 100644
index 00000000..621f3841
--- /dev/null
+++ b/tests/core/stream_muxer/test_read_write_lock.py
@@ -0,0 +1,590 @@
+from typing import Any, cast
+from unittest.mock import AsyncMock, MagicMock, patch
+
+import pytest
+import trio
+from trio.testing import wait_all_tasks_blocked
+
+from libp2p.stream_muxer.exceptions import (
+    MuxedConnUnavailable,
+)
+from libp2p.stream_muxer.mplex.constants import HeaderTags
+from libp2p.stream_muxer.mplex.datastructures import StreamID
+from libp2p.stream_muxer.mplex.exceptions import (
+    MplexStreamClosed,
+    MplexStreamEOF,
+    MplexStreamReset,
+)
+from libp2p.stream_muxer.mplex.mplex_stream import MplexStream
+
+
+class MockMuxedConn:
+    """A mock Mplex connection for testing purposes."""
+
+    def __init__(self):
+        self.sent_messages = []
+        self.streams: dict[StreamID, MplexStream] = {}
+        self.streams_lock = trio.Lock()
+        self.is_unavailable = False
+
+    async def send_message(
+        self, flag: HeaderTags, data: bytes | None, stream_id: StreamID
+    ) -> None:
+        """Mocks sending a message over the connection."""
+        if self.is_unavailable:
+            raise MuxedConnUnavailable("Connection is unavailable")
+        self.sent_messages.append((flag, data, stream_id))
+        # Yield to allow other tasks to run
+        await trio.lowlevel.checkpoint()
+
+    def get_remote_address(self) -> tuple[str, int]:
+        """Mocks getting the remote address."""
+        return "127.0.0.1", 4001
+
+
+@pytest.fixture
+async def mplex_stream():
+    """Provides a fully initialized MplexStream and its communication channels."""
+    # Use a buffered channel to prevent deadlocks in simple tests
+    send_chan, recv_chan = trio.open_memory_channel(10)
+    stream_id = StreamID(1, is_initiator=True)
+    muxed_conn = MockMuxedConn()
+    stream = MplexStream("test-stream", stream_id, cast(Any, muxed_conn), recv_chan)
+    muxed_conn.streams[stream_id] = stream
+
+    yield stream, send_chan, muxed_conn
+
+    # Cleanup: Close channels and reset stream state
+    await send_chan.aclose()
+    await recv_chan.aclose()
+    # Reset stream state to prevent cross-test contamination
+    stream.event_local_closed = trio.Event()
+    stream.event_remote_closed = trio.Event()
+    stream.event_reset = trio.Event()
+
+
+# ===============================================
+# 1. Tests for Stream-Level Lock Integration
+# ===============================================
+
+
+@pytest.mark.trio
+async def test_stream_write_is_protected_by_rwlock(mplex_stream):
+    """Verify that stream.write() acquires and releases the write lock."""
+    stream, _, muxed_conn = mplex_stream
+
+    # Mock lock methods
+    original_acquire = stream.rw_lock.acquire_write
+    original_release = stream.rw_lock.release_write
+
+    stream.rw_lock.acquire_write = AsyncMock(wraps=original_acquire)
+    stream.rw_lock.release_write = MagicMock(wraps=original_release)
+
+    await stream.write(b"test data")
+
+    stream.rw_lock.acquire_write.assert_awaited_once()
+    stream.rw_lock.release_write.assert_called_once()
+
+    # Verify the message was actually sent
+    assert len(muxed_conn.sent_messages) == 1
+    flag, data, stream_id = muxed_conn.sent_messages[0]
+    assert flag == HeaderTags.MessageInitiator
+    assert data == b"test data"
+    assert stream_id == stream.stream_id
+
+
+@pytest.mark.trio
+async def test_stream_read_is_protected_by_rwlock(mplex_stream):
+    """Verify that stream.read() acquires and releases the read lock."""
+    stream, send_chan, _ = mplex_stream
+
+    # Mock lock methods
+    original_acquire = stream.rw_lock.acquire_read
+    original_release = stream.rw_lock.release_read
+
+    stream.rw_lock.acquire_read = AsyncMock(wraps=original_acquire)
+    stream.rw_lock.release_read = AsyncMock(wraps=original_release)
+
+    await send_chan.send(b"hello")
+    result = await stream.read(5)
+
+    stream.rw_lock.acquire_read.assert_awaited_once()
+    stream.rw_lock.release_read.assert_awaited_once()
+    assert result == b"hello"
+
+
+@pytest.mark.trio
+async def test_multiple_readers_can_coexist(mplex_stream):
+    """Verify multiple readers can operate concurrently."""
+    stream, send_chan, _ = mplex_stream
+
+    # Send enough data for both reads
+    await send_chan.send(b"data1")
+    await send_chan.send(b"data2")
+
+    # Track lock acquisition order
+    acquisition_order = []
+    release_order = []
+
+    # Patch lock methods to track concurrency
+    original_acquire = stream.rw_lock.acquire_read
+    original_release = stream.rw_lock.release_read
+
+    async def tracked_acquire():
+        nonlocal acquisition_order
+        acquisition_order.append("start")
+        await original_acquire()
+        acquisition_order.append("acquired")
+
+    async def tracked_release():
+        nonlocal release_order
+        release_order.append("start")
+        await original_release()
+        release_order.append("released")
+
+    with (
+        patch.object(
+            stream.rw_lock, "acquire_read", side_effect=tracked_acquire, autospec=True
+        ),
+        patch.object(
+            stream.rw_lock, "release_read", side_effect=tracked_release, autospec=True
+        ),
+    ):
+        # Execute concurrent reads
+        async with trio.open_nursery() as nursery:
+            nursery.start_soon(stream.read, 5)
+            nursery.start_soon(stream.read, 5)
+
+    # Verify both reads happened
+    assert acquisition_order.count("start") == 2
+    assert acquisition_order.count("acquired") == 2
+    assert release_order.count("start") == 2
+    assert release_order.count("released") == 2
+
+
+@pytest.mark.trio
+async def test_writer_blocks_readers(mplex_stream):
+    """Verify that a writer blocks all readers and new readers queue behind."""
+    stream, send_chan, _ = mplex_stream
+
+    writer_acquired = trio.Event()
+    readers_ready = trio.Event()
+    writer_finished = trio.Event()
+    all_readers_started = trio.Event()
+    all_readers_done = trio.Event()
+
+    counters = {"reader_start_count": 0, "reader_done_count": 0}
+    reader_target = 3
+    reader_start_lock = trio.Lock()
+
+    # Patch write lock to control test flow
+    original_acquire_write = stream.rw_lock.acquire_write
+    original_release_write = stream.rw_lock.release_write
+
+    async def tracked_acquire_write():
+        await original_acquire_write()
+        writer_acquired.set()
+        # Wait for readers to queue up
+        await readers_ready.wait()
+
+    # Must be synchronous since real release_write is sync
+    def tracked_release_write():
+        original_release_write()
+        writer_finished.set()
+
+    with (
+        patch.object(
+            stream.rw_lock, "acquire_write", side_effect=tracked_acquire_write
+        ),
+        patch.object(
+            stream.rw_lock, "release_write", side_effect=tracked_release_write
+        ),
+    ):
+        async with trio.open_nursery() as nursery:
+            # Start writer
+            nursery.start_soon(stream.write, b"test")
+            await writer_acquired.wait()
+
+            # Start readers
+            async def reader_task():
+                async with reader_start_lock:
+                    counters["reader_start_count"] += 1
+                    if counters["reader_start_count"] == reader_target:
+                        all_readers_started.set()
+
+                try:
+                    # This will block until data is available
+                    await stream.read(5)
+                except (MplexStreamReset, MplexStreamEOF):
+                    pass
+                finally:
+                    async with reader_start_lock:
+                        counters["reader_done_count"] += 1
+                        if counters["reader_done_count"] == reader_target:
+                            all_readers_done.set()
+
+            for _ in range(reader_target):
+                nursery.start_soon(reader_task)
+
+            # Wait until all readers are started
+            await all_readers_started.wait()
+
+            # Let the writer finish and release the lock
+            readers_ready.set()
+            await writer_finished.wait()
+
+            # Send data to unblock the readers
+            for i in range(reader_target):
+                await send_chan.send(b"data" + str(i).encode())
+
+            # Wait for all readers to finish
+            await all_readers_done.wait()
+
+
+@pytest.mark.trio
+async def test_writer_waits_for_readers(mplex_stream):
+    """Verify a writer waits for existing readers to complete."""
+    stream, send_chan, _ = mplex_stream
+    readers_started = trio.Event()
+    writer_entered = trio.Event()
+    writer_acquiring = trio.Event()
+    readers_finished = trio.Event()
+
+    # Send data for readers
+    await send_chan.send(b"data1")
+    await send_chan.send(b"data2")
+
+    # Patch read lock to control test flow
+    original_acquire_read = stream.rw_lock.acquire_read
+
+    async def tracked_acquire_read():
+        await original_acquire_read()
+        readers_started.set()
+        # Wait until readers are allowed to finish
+        await readers_finished.wait()
+
+    # Patch write lock to detect when writer is blocked
+    original_acquire_write = stream.rw_lock.acquire_write
+
+    async def tracked_acquire_write():
+        writer_acquiring.set()
+        await original_acquire_write()
+        writer_entered.set()
+
+    with (
+        patch.object(stream.rw_lock, "acquire_read", side_effect=tracked_acquire_read),
+        patch.object(
+            stream.rw_lock, "acquire_write", side_effect=tracked_acquire_write
+        ),
+    ):
+        async with trio.open_nursery() as nursery:
+            # Start readers
+            nursery.start_soon(stream.read, 5)
+            nursery.start_soon(stream.read, 5)
+
+            # Wait for at least one reader to acquire the lock
+            await readers_started.wait()
+
+            # Start writer (should block)
+            nursery.start_soon(stream.write, b"test")
+
+            # Wait for writer to start acquiring lock
+            await writer_acquiring.wait()
+
+            # Verify writer hasn't entered critical section
+            assert not writer_entered.is_set()
+
+            # Allow readers to finish
+            readers_finished.set()
+
+            # Verify writer can proceed
+            await writer_entered.wait()
+
+
+@pytest.mark.trio
+async def test_lock_behavior_during_cancellation(mplex_stream):
+    """Verify that a lock is released when a task holding it is cancelled."""
+    stream, _, _ = mplex_stream
+
+    reader_acquired_lock = trio.Event()
+
+    async def cancellable_reader(task_status):
+        async with stream.rw_lock.read_lock():
+            reader_acquired_lock.set()
+            task_status.started()
+            # Wait indefinitely until cancelled.
+            await trio.sleep_forever()
+
+    async with trio.open_nursery() as nursery:
+        # Start the reader and wait for it to acquire the lock.
+        await nursery.start(cancellable_reader)
+        await reader_acquired_lock.wait()
+
+        # Now that the reader has the lock, cancel the nursery.
+        # This will cancel the reader task, and its lock should be released.
+        nursery.cancel_scope.cancel()
+
+    # After the nursery is cancelled, the reader should have released the lock.
+    # To verify, we try to acquire a write lock. If the read lock was not
+    # released, this will time out.
+    with trio.move_on_after(1) as cancel_scope:
+        async with stream.rw_lock.write_lock():
+            pass
+    if cancel_scope.cancelled_caught:
+        pytest.fail(
+            "Write lock could not be acquired after a cancelled reader, "
+            "indicating the read lock was not released."
+        )
+
+
+@pytest.mark.trio
+async def test_concurrent_read_write_sequence(mplex_stream):
+    """Verify complex sequence of interleaved reads and writes."""
+    stream, send_chan, _ = mplex_stream
+    results = []
+    # Use a mock to intercept writes and feed them back to the read channel
+    original_write = stream.write
+
+    reader1_finished = trio.Event()
+    writer1_finished = trio.Event()
+    reader2_finished = trio.Event()
+
+    async def mocked_write(data: bytes) -> None:
+        await original_write(data)
+        # Simulate the other side receiving the data and sending a response
+        # by putting data into the read channel.
+        await send_chan.send(data)
+
+    with patch.object(stream, "write", wraps=mocked_write) as patched_write:
+        async with trio.open_nursery() as nursery:
+            # Test scenario:
+            # 1. Reader 1 starts, waits for data.
+            # 2. Writer 1 writes, which gets fed back to the stream.
+            # 3. Reader 2 starts, reads what Writer 1 wrote.
+            # 4. Writer 2 writes.
+
+            async def reader1():
+                nonlocal results
+                results.append("R1 start")
+                data = await stream.read(5)
+                results.append(data)
+                results.append("R1 done")
+                reader1_finished.set()
+
+            async def writer1():
+                nonlocal results
+                await reader1_finished.wait()
+                results.append("W1 start")
+                await stream.write(b"write1")
+                results.append("W1 done")
+                writer1_finished.set()
+
+            async def reader2():
+                nonlocal results
+                await writer1_finished.wait()
+                # This will read the data from writer1
+                results.append("R2 start")
+                data = await stream.read(6)
+                results.append(data)
+                results.append("R2 done")
+                reader2_finished.set()
+
+            async def writer2():
+                nonlocal results
+                await reader2_finished.wait()
+                results.append("W2 start")
+                await stream.write(b"write2")
+                results.append("W2 done")
+
+            # Execute sequence
+            nursery.start_soon(reader1)
+            nursery.start_soon(writer1)
+            nursery.start_soon(reader2)
+            nursery.start_soon(writer2)
+
+            await send_chan.send(b"data1")
+
+    # Verify sequence and that write was called
+    assert patched_write.call_count == 2
+    assert results == [
+        "R1 start",
+        b"data1",
+        "R1 done",
+        "W1 start",
+        "W1 done",
+        "R2 start",
+        b"write1",
+        "R2 done",
+        "W2 start",
+        "W2 done",
+    ]
+
+
+# ===============================================
+# 2. Tests for Reset, EOF, and Close Interactions
+# ===============================================
+
+
+@pytest.mark.trio
+async def test_read_after_remote_close_triggers_eof(mplex_stream):
+    """Verify reading from a remotely closed stream returns EOF correctly."""
+    stream, send_chan, _ = mplex_stream
+
+    # Send some data that can be read first
+    await send_chan.send(b"data")
+    # Close the channel to signify no more data will ever arrive
+    await send_chan.aclose()
+
+    # Mark the stream as remotely closed
+    stream.event_remote_closed.set()
+
+    # The first read should succeed, consuming the buffered data
+    data = await stream.read(4)
+    assert data == b"data"
+
+    # Now that the buffer is empty and the channel is closed, this should raise EOF
+    with pytest.raises(MplexStreamEOF):
+        await stream.read(1)
+
+
+@pytest.mark.trio
+async def test_read_on_closed_stream_raises_eof(mplex_stream):
+    """Test that reading from a closed stream with no data raises EOF."""
+    stream, send_chan, _ = mplex_stream
+    stream.event_remote_closed.set()
+    await send_chan.aclose()  # Ensure the channel is closed
+
+    # Reading from a stream that is closed and has no data should raise EOF
+    with pytest.raises(MplexStreamEOF):
+        await stream.read(100)
+
+
+@pytest.mark.trio
+async def test_write_to_locally_closed_stream_raises(mplex_stream):
+    """Verify writing to a locally closed stream raises MplexStreamClosed."""
+    stream, _, _ = mplex_stream
+    stream.event_local_closed.set()
+
+    with pytest.raises(MplexStreamClosed):
+        await stream.write(b"this should fail")
+
+
+@pytest.mark.trio
+async def test_read_from_reset_stream_raises(mplex_stream):
+    """Verify reading from a reset stream raises MplexStreamReset."""
+    stream, _, _ = mplex_stream
+    stream.event_reset.set()
+
+    with pytest.raises(MplexStreamReset):
+        await stream.read(10)
+
+
+@pytest.mark.trio
+async def test_write_to_reset_stream_raises(mplex_stream):
+    """Verify writing to a reset stream raises MplexStreamClosed."""
+    stream, _, _ = mplex_stream
+    # A stream reset implies it's also locally closed.
+    await stream.reset()
+
+    # The `write` method checks `event_local_closed`, which `reset` sets.
+    with pytest.raises(MplexStreamClosed):
+        await stream.write(b"this should also fail")
+
+
+@pytest.mark.trio
+async def test_stream_reset_cleans_up_resources(mplex_stream):
+    """Verify reset() cleans up stream state and resources."""
+    stream, _, muxed_conn = mplex_stream
+    stream_id = stream.stream_id
+
+    assert stream_id in muxed_conn.streams
+    await stream.reset()
+
+    assert stream.event_reset.is_set()
+    assert stream.event_local_closed.is_set()
+    assert stream.event_remote_closed.is_set()
+    assert (HeaderTags.ResetInitiator, None, stream_id) in muxed_conn.sent_messages
+    assert stream_id not in muxed_conn.streams
+    # Verify the underlying data channel is closed
+    with pytest.raises(trio.ClosedResourceError):
+        await stream.incoming_data_channel.receive()
+
+
+# ===============================================
+# 3. Rigorous Concurrency Tests with Events
+# ===============================================
+
+
+@pytest.mark.trio
+async def test_writer_is_blocked_by_reader_using_events(mplex_stream):
+    """Verify a writer must wait for a reader using trio.Event for synchronization."""
+    stream, _, _ = mplex_stream
+
+    reader_has_lock = trio.Event()
+    writer_finished = trio.Event()
+
+    async def reader():
+        async with stream.rw_lock.read_lock():
+            reader_has_lock.set()
+            # Hold the lock until the writer has finished its attempt
+            await writer_finished.wait()
+
+    async def writer():
+        await reader_has_lock.wait()
+        # This call will now block until the reader releases the lock
+        await stream.write(b"data")
+        writer_finished.set()
+
+    async with trio.open_nursery() as nursery:
+        nursery.start_soon(reader)
+        nursery.start_soon(writer)
+
+        # Verify writer is blocked
+        await wait_all_tasks_blocked()
+        assert not writer_finished.is_set()
+
+        # Signal the reader to finish
+        writer_finished.set()
+
+
+@pytest.mark.trio
+async def test_multiple_readers_can_read_concurrently_using_events(mplex_stream):
+    """Verify that multiple readers can acquire a read lock simultaneously."""
+    stream, _, _ = mplex_stream
+
+    counters = {"readers_in_critical_section": 0}
+    lock = trio.Lock()  # To safely mutate the counter
+
+    reader1_acquired = trio.Event()
+    reader2_acquired = trio.Event()
+    all_readers_finished = trio.Event()
+
+    async def concurrent_reader(event_to_set: trio.Event):
+        async with stream.rw_lock.read_lock():
+            async with lock:
+                counters["readers_in_critical_section"] += 1
+            event_to_set.set()
+            # Wait until all readers have finished before exiting the lock context
+            await all_readers_finished.wait()
+            async with lock:
+                counters["readers_in_critical_section"] -= 1
+
+    async with trio.open_nursery() as nursery:
+        nursery.start_soon(concurrent_reader, reader1_acquired)
+        nursery.start_soon(concurrent_reader, reader2_acquired)
+
+        # Wait for both readers to acquire their locks
+        await reader1_acquired.wait()
+        await reader2_acquired.wait()
+
+        # Check that both were in the critical section at the same time
+        async with lock:
+            assert counters["readers_in_critical_section"] == 2
+
+        # Signal for all readers to finish
+        all_readers_finished.set()
+
+        # Verify they exit cleanly
+        await wait_all_tasks_blocked()
+        async with lock:
+            assert counters["readers_in_critical_section"] == 0