diff --git a/Cargo.lock b/Cargo.lock
index cdf3ed1e04a..0d898d0360b 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -2387,7 +2387,6 @@ dependencies = [
  "libp2p-kad",
  "libp2p-mdns",
  "libp2p-metrics",
- "libp2p-mplex",
  "libp2p-noise",
  "libp2p-perf",
  "libp2p-ping",
@@ -2591,10 +2590,10 @@ dependencies = [
  "instant",
  "libp2p-core",
  "libp2p-identity",
- "libp2p-mplex",
  "libp2p-noise",
  "libp2p-swarm",
  "libp2p-swarm-test",
+ "libp2p-yamux",
  "log",
  "prometheus-client",
  "quick-protobuf",
diff --git a/examples/chat-example/src/main.rs b/examples/chat-example/src/main.rs
index 2c038724c37..338b2e360ec 100644
--- a/examples/chat-example/src/main.rs
+++ b/examples/chat-example/src/main.rs
@@ -74,7 +74,7 @@ async fn main() -> Result<(), Box<dyn Error>> {
     let local_peer_id = PeerId::from(id_keys.public());
     println!("Local peer id: {local_peer_id}");
 
-    // Set up an encrypted DNS-enabled TCP Transport over the Mplex protocol.
+    // Set up an encrypted DNS-enabled TCP Transport over the yamux protocol.
     let tcp_transport = tcp::async_io::Transport::new(tcp::Config::default().nodelay(true))
         .upgrade(upgrade::Version::V1Lazy)
         .authenticate(noise::Config::new(&id_keys).expect("signing libp2p-noise static keypair"))
diff --git a/examples/ipfs-kad/Cargo.toml b/examples/ipfs-kad/Cargo.toml
index 7e156572781..701e4543408 100644
--- a/examples/ipfs-kad/Cargo.toml
+++ b/examples/ipfs-kad/Cargo.toml
@@ -10,4 +10,4 @@ async-std = { version = "1.12", features = ["attributes"] }
 async-trait = "0.1"
 env_logger = "0.10"
 futures = "0.3.28"
-libp2p = { path = "../../libp2p", features = ["async-std", "dns", "kad", "mplex", "noise", "tcp", "websocket", "yamux"] }
+libp2p = { path = "../../libp2p", features = ["async-std", "dns", "kad", "noise", "tcp", "websocket", "yamux"] }
diff --git a/examples/ipfs-kad/src/main.rs b/examples/ipfs-kad/src/main.rs
index 9799ca8df0a..42735de2741 100644
--- a/examples/ipfs-kad/src/main.rs
+++ b/examples/ipfs-kad/src/main.rs
@@ -48,7 +48,7 @@ async fn main() -> Result<(), Box<dyn Error>> {
     let local_key = identity::Keypair::generate_ed25519();
     let local_peer_id = PeerId::from(local_key.public());
 
-    // Set up a an encrypted DNS-enabled TCP Transport over the Mplex protocol
+    // Set up a an encrypted DNS-enabled TCP Transport over the yamux protocol
     let transport = development_transport(local_key).await?;
 
     // Create a swarm to manage peers and events.
diff --git a/libp2p/CHANGELOG.md b/libp2p/CHANGELOG.md
index 18206718799..e073fccf7dd 100644
--- a/libp2p/CHANGELOG.md
+++ b/libp2p/CHANGELOG.md
@@ -12,9 +12,15 @@
   
 - Rename `NetworkBehaviour::OutEvent` to `NetworkBehaviour::ToSwarm`, `ConnectionHandler::InEvent` to `ConnectionHandler::FromBehaviour`, `ConnectionHandler::OutEvent` to `ConnectionHandler::ToBehaviour`. See [PR 3848].
 
-[PR 3746]: https://github.com/libp2p/rust-libp2p/pull/3746
+- Remove deprecated `mplex` module.
+  You can still depend on `libp2p-mplex` directly but we strongly encourage to migrate to `yamux`.
+  This also removes `mplex` from the `development_transport` and `tokio_development_transport` functions.
+  See [PR 3920].
+
 [PR 3715]: https://github.com/libp2p/rust-libp2p/pull/3715
+[PR 3746]: https://github.com/libp2p/rust-libp2p/pull/3746
 [PR 3848]: https://github.com/libp2p/rust-libp2p/pull/3848
+[PR 3920]: https://github.com/libp2p/rust-libp2p/pull/3920
 
 ## 0.51.3
 
diff --git a/libp2p/Cargo.toml b/libp2p/Cargo.toml
index b4fa79d6343..95cd9c08681 100644
--- a/libp2p/Cargo.toml
+++ b/libp2p/Cargo.toml
@@ -26,7 +26,6 @@ full = [
     "macros",
     "mdns",
     "metrics",
-    "mplex",
     "noise",
     "perf",
     "ping",
@@ -65,7 +64,6 @@ kad = ["dep:libp2p-kad", "libp2p-metrics?/kad"]
 macros = ["libp2p-swarm/macros"]
 mdns = ["dep:libp2p-mdns"]
 metrics = ["dep:libp2p-metrics"]
-mplex = ["dep:libp2p-mplex"]
 noise = ["dep:libp2p-noise"]
 perf = ["dep:libp2p-perf"]
 ping = ["dep:libp2p-ping", "libp2p-metrics?/ping"]
@@ -106,7 +104,6 @@ libp2p-identify = { workspace = true, optional = true }
 libp2p-identity = { workspace = true }
 libp2p-kad = { workspace = true, optional = true }
 libp2p-metrics = { workspace = true, optional = true }
-libp2p-mplex = { workspace = true, optional = true }
 libp2p-noise = { workspace = true, optional = true }
 libp2p-ping = { workspace = true, optional = true }
 libp2p-plaintext = { workspace = true, optional = true }
@@ -144,7 +141,6 @@ env_logger = "0.10.0"
 clap = { version = "4.1.6", features = ["derive"] }
 tokio = { version = "1.15", features = ["io-util", "io-std", "macros", "rt", "rt-multi-thread"] }
 
-libp2p-mplex = { workspace = true }
 libp2p-noise = { workspace = true }
 libp2p-tcp = { workspace = true, features = ["tokio"] }
 
diff --git a/libp2p/src/lib.rs b/libp2p/src/lib.rs
index f086c2872f4..917c1c86edc 100644
--- a/libp2p/src/lib.rs
+++ b/libp2p/src/lib.rs
@@ -82,13 +82,6 @@ pub use libp2p_mdns as mdns;
 #[cfg(feature = "metrics")]
 #[doc(inline)]
 pub use libp2p_metrics as metrics;
-#[cfg(feature = "mplex")]
-#[deprecated(
-    note = "`mplex` is not recommended anymore. Please use `yamux` instead or depend on `libp2p-mplex` directly if you need it for legacy use cases."
-)]
-pub mod mplex {
-    pub use libp2p_mplex::*;
-}
 #[cfg(feature = "noise")]
 #[doc(inline)]
 pub use libp2p_noise as noise;
@@ -184,7 +177,7 @@ pub use libp2p_swarm::{Stream, StreamProtocol};
 ///  * DNS resolution.
 ///  * Noise protocol encryption.
 ///  * Websockets.
-///  * Both Yamux and Mplex for substream multiplexing.
+///  * Yamux for substream multiplexing.
 ///
 /// All async I/O of the transport is based on `async-std`.
 ///
@@ -198,7 +191,6 @@ pub use libp2p_swarm::{Stream, StreamProtocol};
     ),
     feature = "websocket",
     feature = "noise",
-    feature = "mplex",
     feature = "yamux"
 ))]
 #[cfg_attr(
@@ -231,11 +223,7 @@ pub async fn development_transport(
     Ok(transport
         .upgrade(core::upgrade::Version::V1)
         .authenticate(noise::Config::new(&keypair).unwrap())
-        .multiplex(core::upgrade::SelectUpgrade::new(
-            yamux::Config::default(),
-            #[allow(deprecated)]
-            mplex::MplexConfig::default(),
-        ))
+        .multiplex(yamux::Config::default())
         .timeout(std::time::Duration::from_secs(20))
         .boxed())
 }
@@ -245,7 +233,7 @@ pub async fn development_transport(
 ///  * DNS resolution.
 ///  * Noise protocol encryption.
 ///  * Websockets.
-///  * Both Yamux and Mplex for substream multiplexing.
+///  * Yamux for substream multiplexing.
 ///
 /// All async I/O of the transport is based on `tokio`.
 ///
@@ -259,7 +247,6 @@ pub async fn development_transport(
     ),
     feature = "websocket",
     feature = "noise",
-    feature = "mplex",
     feature = "yamux"
 ))]
 #[cfg_attr(
@@ -288,11 +275,7 @@ pub fn tokio_development_transport(
     Ok(transport
         .upgrade(core::upgrade::Version::V1)
         .authenticate(noise::Config::new(&keypair).unwrap())
-        .multiplex(core::upgrade::SelectUpgrade::new(
-            yamux::Config::default(),
-            #[allow(deprecated)]
-            mplex::MplexConfig::default(),
-        ))
+        .multiplex(yamux::Config::default())
         .timeout(std::time::Duration::from_secs(20))
         .boxed())
 }
diff --git a/libp2p/src/transport_ext.rs b/libp2p/src/transport_ext.rs
index b51b8e8298a..8f7c16574f6 100644
--- a/libp2p/src/transport_ext.rs
+++ b/libp2p/src/transport_ext.rs
@@ -43,7 +43,7 @@ pub trait TransportExt: Transport {
     /// # Example
     ///
     /// ```
-    /// use libp2p_mplex as mplex;
+    /// use libp2p_yamux as yamux;
     /// use libp2p_noise as noise;
     /// use libp2p_tcp as tcp;
     /// use libp2p::{
@@ -61,7 +61,7 @@ pub trait TransportExt: Transport {
     ///         noise::Config::new(&id_keys)
     ///             .expect("Signing libp2p-noise static DH keypair failed."),
     ///     )
-    ///     .multiplex(mplex::MplexConfig::new())
+    ///     .multiplex(yamux::Config::default())
     ///     .boxed();
     ///
     /// let (transport, sinks) = transport.with_bandwidth_logging();
diff --git a/libp2p/src/tutorials/ping.rs b/libp2p/src/tutorials/ping.rs
index 295e37e24b1..b698c6ab3bb 100644
--- a/libp2p/src/tutorials/ping.rs
+++ b/libp2p/src/tutorials/ping.rs
@@ -55,7 +55,7 @@
 //!        edition = "2021"
 //!
 //!    [dependencies]
-//!        libp2p = { version = "0.50", features = ["tcp", "dns", "async-std", "noise", "mplex", "yamux", "websocket", "ping", "macros"] }
+//!        libp2p = { version = "0.50", features = ["tcp", "dns", "async-std", "noise", "yamux", "websocket", "ping", "macros"] }
 //!        futures = "0.3.21"
 //!        async-std = { version = "1.12.0", features = ["attributes"] }
 //!    ```
diff --git a/protocols/gossipsub/Cargo.toml b/protocols/gossipsub/Cargo.toml
index 813428bc008..80645f509ba 100644
--- a/protocols/gossipsub/Cargo.toml
+++ b/protocols/gossipsub/Cargo.toml
@@ -42,7 +42,7 @@ async-std = { version = "1.6.3", features = ["unstable"] }
 env_logger = "0.10.0"
 hex = "0.4.2"
 libp2p-core = { workspace = true }
-libp2p-mplex = { workspace = true }
+libp2p-yamux = { workspace = true }
 libp2p-noise = { workspace = true }
 libp2p-swarm-test = { workspace = true }
 quickcheck = { workspace = true }
diff --git a/protocols/gossipsub/src/lib.rs b/protocols/gossipsub/src/lib.rs
index cebd24444ee..b5ea9999a5a 100644
--- a/protocols/gossipsub/src/lib.rs
+++ b/protocols/gossipsub/src/lib.rs
@@ -99,12 +99,12 @@
 //! let local_key = identity::Keypair::generate_ed25519();
 //! let local_peer_id = local_key.public().to_peer_id();
 //!
-//! // Set up an encrypted TCP Transport over the Mplex
+//! // Set up an encrypted TCP Transport over yamux
 //! // This is test transport (memory).
 //! let transport = MemoryTransport::default()
 //!            .upgrade(libp2p_core::upgrade::Version::V1)
 //!            .authenticate(libp2p_noise::Config::new(&local_key).unwrap())
-//!            .multiplex(libp2p_mplex::MplexConfig::new())
+//!            .multiplex(libp2p_yamux::Config::default())
 //!            .boxed();
 //!
 //! // Create a Gossipsub topic