diff --git a/.gitignore b/.gitignore
index e46cc8aa..e17714b5 100644
--- a/.gitignore
+++ b/.gitignore
@@ -178,3 +178,7 @@ env.bak/
 #lockfiles
 uv.lock
 poetry.lock
+tests/interop/js_libp2p/js_node/node_modules/
+tests/interop/js_libp2p/js_node/package-lock.json
+tests/interop/js_libp2p/js_node/src/node_modules/
+tests/interop/js_libp2p/js_node/src/package-lock.json
diff --git a/libp2p/transport/__init__.py b/libp2p/transport/__init__.py
index e69de29b..62cc5f06 100644
--- a/libp2p/transport/__init__.py
+++ b/libp2p/transport/__init__.py
@@ -0,0 +1,7 @@
+from .tcp.tcp import TCP
+from .websocket.transport import WebsocketTransport
+
+__all__ = [
+    "TCP",
+    "WebsocketTransport",
+]
diff --git a/libp2p/transport/websocket/connection.py b/libp2p/transport/websocket/connection.py
new file mode 100644
index 00000000..b8c23603
--- /dev/null
+++ b/libp2p/transport/websocket/connection.py
@@ -0,0 +1,49 @@
+from trio.abc import Stream
+
+from libp2p.io.abc import ReadWriteCloser
+from libp2p.io.exceptions import IOException
+
+
+class P2PWebSocketConnection(ReadWriteCloser):
+    """
+    Wraps a raw trio.abc.Stream from an established websocket connection.
+    This bypasses message-framing issues and provides the raw stream
+    that libp2p protocols expect.
+    """
+
+    _stream: Stream
+
+    def __init__(self, stream: Stream):
+        self._stream = stream
+
+    async def write(self, data: bytes) -> None:
+        try:
+            await self._stream.send_all(data)
+        except Exception as e:
+            raise IOException from e
+
+    async def read(self, n: int | None = None) -> bytes:
+        """
+        Read up to n bytes (if n is given), else read up to 64KiB.
+        """
+        try:
+            if n is None:
+                # read a reasonable chunk
+                return await self._stream.receive_some(2**16)
+            return await self._stream.receive_some(n)
+        except Exception as e:
+            raise IOException from e
+
+    async def close(self) -> None:
+        await self._stream.aclose()
+
+    def get_remote_address(self) -> tuple[str, int] | None:
+        sock = getattr(self._stream, "socket", None)
+        if sock:
+            try:
+                addr = sock.getpeername()
+                if isinstance(addr, tuple) and len(addr) >= 2:
+                    return str(addr[0]), int(addr[1])
+            except OSError:
+                return None
+        return None
diff --git a/libp2p/transport/websocket/listener.py b/libp2p/transport/websocket/listener.py
new file mode 100644
index 00000000..be3cc035
--- /dev/null
+++ b/libp2p/transport/websocket/listener.py
@@ -0,0 +1,81 @@
+import logging
+import socket
+from typing import Any
+
+from multiaddr import Multiaddr
+import trio
+from trio_typing import TaskStatus
+from trio_websocket import serve_websocket
+
+from libp2p.abc import IListener
+from libp2p.custom_types import THandler
+from libp2p.network.connection.raw_connection import RawConnection
+
+from .connection import P2PWebSocketConnection
+
+logger = logging.getLogger("libp2p.transport.websocket.listener")
+
+
+class WebsocketListener(IListener):
+    """
+    Listen on /ip4/.../tcp/.../ws addresses, handshake WS, wrap into RawConnection.
+    """
+
+    def __init__(self, handler: THandler) -> None:
+        self._handler = handler
+        self._server = None
+
+    async def listen(self, maddr: Multiaddr, nursery: trio.Nursery) -> bool:
+        addr_str = str(maddr)
+        if addr_str.endswith("/wss"):
+            raise NotImplementedError("/wss (TLS) not yet supported")
+
+        host = (
+            maddr.value_for_protocol("ip4")
+            or maddr.value_for_protocol("ip6")
+            or maddr.value_for_protocol("dns")
+            or maddr.value_for_protocol("dns4")
+            or maddr.value_for_protocol("dns6")
+            or "0.0.0.0"
+        )
+        port = int(maddr.value_for_protocol("tcp"))
+
+        async def serve(
+            task_status: TaskStatus[Any] = trio.TASK_STATUS_IGNORED,
+        ) -> None:
+            # positional ssl_context=None
+            self._server = await serve_websocket(
+                self._handle_connection, host, port, None
+            )
+            task_status.started()
+            await self._server.wait_closed()
+
+        await nursery.start(serve)
+        return True
+
+    async def _handle_connection(self, websocket: Any) -> None:
+        try:
+            # use raw transport_stream
+            conn = P2PWebSocketConnection(websocket.stream)
+            raw = RawConnection(conn, initiator=False)
+            await self._handler(raw)
+        except Exception as e:
+            logger.debug("WebSocket connection error: %s", e)
+
+    def get_addrs(self) -> tuple[Multiaddr, ...]:
+        if not self._server or not self._server.sockets:
+            return ()
+        addrs = []
+        for sock in self._server.sockets:
+            host, port = sock.getsockname()[:2]
+            if sock.family == socket.AF_INET6:
+                addr = Multiaddr(f"/ip6/{host}/tcp/{port}/ws")
+            else:
+                addr = Multiaddr(f"/ip4/{host}/tcp/{port}/ws")
+            addrs.append(addr)
+        return tuple(addrs)
+
+    async def close(self) -> None:
+        if self._server:
+            self._server.close()
+            await self._server.wait_closed()
diff --git a/libp2p/transport/websocket/transport.py b/libp2p/transport/websocket/transport.py
new file mode 100644
index 00000000..4085b556
--- /dev/null
+++ b/libp2p/transport/websocket/transport.py
@@ -0,0 +1,49 @@
+from multiaddr import Multiaddr
+from trio_websocket import open_websocket_url
+
+from libp2p.abc import IListener, ITransport
+from libp2p.custom_types import THandler
+from libp2p.network.connection.raw_connection import RawConnection
+from libp2p.transport.exceptions import OpenConnectionError
+
+from .connection import P2PWebSocketConnection
+from .listener import WebsocketListener
+
+
+class WebsocketTransport(ITransport):
+    """
+    Libp2p WebSocket transport: dial and listen on /ip4/.../tcp/.../ws
+    """
+
+    async def dial(self, maddr: Multiaddr) -> RawConnection:
+        text = str(maddr)
+        if text.endswith("/wss"):
+            raise NotImplementedError("/wss (TLS) not yet supported")
+        if not text.endswith("/ws"):
+            raise ValueError(f"WebsocketTransport only supports /ws, got {maddr}")
+
+        host = (
+            maddr.value_for_protocol("ip4")
+            or maddr.value_for_protocol("ip6")
+            or maddr.value_for_protocol("dns")
+            or maddr.value_for_protocol("dns4")
+            or maddr.value_for_protocol("dns6")
+        )
+        if host is None:
+            raise ValueError(f"No host protocol found in {maddr}")
+
+        port = int(maddr.value_for_protocol("tcp"))
+        uri = f"ws://{host}:{port}"
+
+        try:
+            async with open_websocket_url(uri, ssl_context=None) as ws:
+                conn = P2PWebSocketConnection(ws.stream)  # type: ignore[attr-defined]
+                return RawConnection(conn, initiator=True)
+        except Exception as e:
+            raise OpenConnectionError(f"Failed to dial WebSocket {maddr}: {e}") from e
+
+    def create_listener(self, handler: THandler) -> IListener:  # type: ignore[override]
+        """
+        The type checker is incorrectly reporting this as an inconsistent override.
+        """
+        return WebsocketListener(handler)
diff --git a/pyproject.toml b/pyproject.toml
index 259c6c17..b5feab5e 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -30,6 +30,7 @@ dependencies = [
     "trio-typing>=0.0.4",
     "trio>=0.26.0",
     "fastecdsa==2.3.2; sys_platform != 'win32'",
+    "trio-websocket>=0.11.0",
     "zeroconf (>=0.147.0,<0.148.0)",
 ]
 classifiers = [
diff --git a/tests/interop/__init__.py b/tests/interop/__init__.py
new file mode 100644
index 00000000..e69de29b
diff --git a/tests/interop/js_libp2p/js_node/src/package.json b/tests/interop/js_libp2p/js_node/src/package.json
new file mode 100644
index 00000000..1a7a2547
--- /dev/null
+++ b/tests/interop/js_libp2p/js_node/src/package.json
@@ -0,0 +1,18 @@
+{
+  "name": "src",
+  "version": "1.0.0",
+  "main": "ping.js",
+  "scripts": {
+    "test": "echo \"Error: no test specified\" && exit 1"
+  },
+  "keywords": [],
+  "author": "",
+  "license": "ISC",
+  "description": "",
+  "dependencies": {
+    "@libp2p/ping": "^2.0.36",
+    "@libp2p/websockets": "^9.2.18",
+    "libp2p": "^2.9.0",
+    "multiaddr": "^10.0.1"
+  }
+}
diff --git a/tests/interop/js_libp2p/js_node/src/ws_ping_node.mjs b/tests/interop/js_libp2p/js_node/src/ws_ping_node.mjs
new file mode 100644
index 00000000..18988b43
--- /dev/null
+++ b/tests/interop/js_libp2p/js_node/src/ws_ping_node.mjs
@@ -0,0 +1,35 @@
+import { createLibp2p }          from 'libp2p'
+import { webSockets }            from '@libp2p/websockets'
+import { ping }                  from '@libp2p/ping'
+import { plaintext }             from '@libp2p/insecure'
+import { mplex }                 from '@libp2p/mplex'
+
+async function main() {
+  const node = await createLibp2p({
+    transports:           [ webSockets() ],
+    connectionEncryption: [ plaintext() ],
+    streamMuxers:         [ mplex() ],
+    services: {
+      // installs /ipfs/ping/1.0.0 handler
+      ping: ping()
+    },
+    addresses: {
+      listen: ['/ip4/127.0.0.1/tcp/0/ws']
+    }
+  })
+
+  await node.start()
+
+  console.log(node.peerId.toString())
+  for (const addr of node.getMultiaddrs()) {
+    console.log(addr.toString())
+  }
+
+  // Keep the process alive
+  await new Promise(() => {})
+}
+
+main().catch(err => {
+  console.error(err)
+  process.exit(1)
+})
diff --git a/tests/interop/test_js_ws_ping.py b/tests/interop/test_js_ws_ping.py
new file mode 100644
index 00000000..813c7cf2
--- /dev/null
+++ b/tests/interop/test_js_ws_ping.py
@@ -0,0 +1,85 @@
+import os
+import signal
+import subprocess
+
+import pytest
+from multiaddr import Multiaddr
+import trio
+from trio.lowlevel import open_process
+
+from libp2p.crypto.secp256k1 import create_new_key_pair
+from libp2p.custom_types import TProtocol
+from libp2p.host.basic_host import BasicHost
+from libp2p.network.swarm import Swarm
+from libp2p.peer.id import ID
+from libp2p.peer.peerinfo import PeerInfo
+from libp2p.peer.peerstore import PeerStore
+from libp2p.security.insecure.transport import InsecureTransport
+from libp2p.stream_muxer.mplex.mplex import MPLEX_PROTOCOL_ID, Mplex
+from libp2p.transport.upgrader import TransportUpgrader
+from libp2p.transport.websocket.transport import WebsocketTransport
+
+PLAINTEXT_PROTOCOL_ID = "/plaintext/1.0.0"
+
+
+@pytest.mark.trio
+async def test_ping_with_js_node():
+    # 1) Path to the JS node script
+    js_node_dir = os.path.join(os.path.dirname(__file__), "js_libp2p", "js_node", "src")
+    script_name = "ws_ping_node.mjs"
+
+    # 2) Launch the JS libp2p node (long-running)
+    proc = await open_process(
+        ["node", script_name],
+        stdout=subprocess.PIPE,
+        stderr=subprocess.DEVNULL,
+        cwd=js_node_dir,
+    )
+    try:
+        # 3) Read first two lines (PeerID and multiaddr)
+        buffer = b""
+        with trio.fail_after(10):
+            while buffer.count(b"\n") < 2:
+                chunk = await proc.stdout.receive_some(1024)  # type: ignore
+                if not chunk:
+                    break
+                buffer += chunk
+
+        lines = buffer.decode().strip().split("\n")
+        peer_id_line, addr_line = lines[0], lines[1]
+        peer_id = ID.from_base58(peer_id_line)
+        maddr = Multiaddr(addr_line)
+
+        # 4) Set up Python host
+        key_pair = create_new_key_pair()
+        py_peer_id = ID.from_pubkey(key_pair.public_key)
+        peer_store = PeerStore()
+        peer_store.add_key_pair(py_peer_id, key_pair)
+
+        upgrader = TransportUpgrader(
+            secure_transports_by_protocol={
+                TProtocol(PLAINTEXT_PROTOCOL_ID): InsecureTransport(key_pair)
+            },
+            muxer_transports_by_protocol={TProtocol(MPLEX_PROTOCOL_ID): Mplex},
+        )
+        transport = WebsocketTransport()
+        swarm = Swarm(py_peer_id, peer_store, upgrader, transport)
+        host = BasicHost(swarm)
+
+        # 5) Connect to JS node
+        peer_info = PeerInfo(peer_id, [maddr])
+        await host.connect(peer_info)
+        assert host.get_network().connections.get(peer_id) is not None
+        await trio.sleep(0.1)
+
+        # 6) Ping protocol
+        stream = await host.new_stream(peer_id, [TProtocol("/ipfs/ping/1.0.0")])
+        await stream.write(b"ping")
+        data = await stream.read(4)
+        assert data == b"pong"
+
+        # 7) Cleanup
+        await host.close()
+    finally:
+        proc.send_signal(signal.SIGTERM)
+        await trio.sleep(0)
diff --git a/tests/transport/__init__.py b/tests/transport/__init__.py
new file mode 100644
index 00000000..e69de29b
diff --git a/tests/transport/test_websocket.py b/tests/transport/test_websocket.py
new file mode 100644
index 00000000..412e1063
--- /dev/null
+++ b/tests/transport/test_websocket.py
@@ -0,0 +1,72 @@
+from collections.abc import Sequence
+from typing import Any
+
+import pytest
+from multiaddr import Multiaddr
+
+from libp2p.crypto.secp256k1 import create_new_key_pair
+from libp2p.custom_types import TProtocol
+from libp2p.host.basic_host import BasicHost
+from libp2p.network.swarm import Swarm
+from libp2p.peer.id import ID
+from libp2p.peer.peerinfo import PeerInfo
+from libp2p.peer.peerstore import PeerStore
+from libp2p.security.insecure.transport import InsecureTransport
+from libp2p.stream_muxer.mplex.mplex import MPLEX_PROTOCOL_ID, Mplex
+from libp2p.transport.upgrader import TransportUpgrader
+from libp2p.transport.websocket.transport import WebsocketTransport
+
+PLAINTEXT_PROTOCOL_ID = "/plaintext/1.0.0"
+
+
+async def make_host(
+    listen_addrs: Sequence[Multiaddr] | None = None,
+) -> tuple[BasicHost, Any | None]:
+    # 1) Identity
+    key_pair = create_new_key_pair()
+    peer_id = ID.from_pubkey(key_pair.public_key)
+    peer_store = PeerStore()
+    peer_store.add_key_pair(peer_id, key_pair)
+
+    # 2) Upgrader
+    upgrader = TransportUpgrader(
+        secure_transports_by_protocol={
+            TProtocol(PLAINTEXT_PROTOCOL_ID): InsecureTransport(key_pair)
+        },
+        muxer_transports_by_protocol={TProtocol(MPLEX_PROTOCOL_ID): Mplex},
+    )
+
+    # 3) Transport + Swarm + Host
+    transport = WebsocketTransport()
+    swarm = Swarm(peer_id, peer_store, upgrader, transport)
+    host = BasicHost(swarm)
+
+    # 4) Optionally run/listen
+    ctx = None
+    if listen_addrs:
+        ctx = host.run(listen_addrs)
+        await ctx.__aenter__()
+
+    return host, ctx
+
+
+@pytest.mark.trio
+async def test_websocket_dial_and_listen():
+    # Start server
+    server_host, server_ctx = await make_host([Multiaddr("/ip4/127.0.0.1/tcp/0/ws")])
+    # Client
+    client_host, _ = await make_host(None)
+
+    # Dial
+    peer_info = PeerInfo(server_host.get_id(), server_host.get_addrs())
+    await client_host.connect(peer_info)
+
+    # Verify connections
+    assert client_host.get_network().connections.get(server_host.get_id())
+    assert server_host.get_network().connections.get(client_host.get_id())
+
+    # Cleanup
+    await client_host.close()
+    if server_ctx:
+        await server_ctx.__aexit__(None, None, None)
+    await server_host.close()