diff --git a/src/lib.rs b/src/lib.rs
index 4d588974..1994a540 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -302,6 +302,10 @@ impl Protocol {
 
     /// Protocol corresponding to `UDP`.
     pub const UDP: Protocol = Protocol(sys::IPPROTO_UDP);
+
+    #[cfg(target_os = "linux")]
+    /// Protocol corresponding to `MPTCP`.
+    pub const MPTCP: Protocol = Protocol(sys::IPPROTO_MPTCP);
 }
 
 impl From<c_int> for Protocol {
diff --git a/src/sys/unix.rs b/src/sys/unix.rs
index b54c2f63..fbe5a171 100644
--- a/src/sys/unix.rs
+++ b/src/sys/unix.rs
@@ -63,6 +63,8 @@ pub(crate) use libc::SOCK_RAW;
 pub(crate) use libc::SOCK_SEQPACKET;
 pub(crate) use libc::{SOCK_DGRAM, SOCK_STREAM};
 // Used in `Protocol`.
+#[cfg(target_os = "linux")]
+pub(crate) use libc::IPPROTO_MPTCP;
 pub(crate) use libc::{IPPROTO_ICMP, IPPROTO_ICMPV6, IPPROTO_TCP, IPPROTO_UDP};
 // Used in `SockAddr`.
 pub(crate) use libc::{
@@ -386,6 +388,8 @@ impl_debug!(
     libc::IPPROTO_ICMPV6,
     libc::IPPROTO_TCP,
     libc::IPPROTO_UDP,
+    #[cfg(target_os = "linux")]
+    libc::IPPROTO_MPTCP,
 );
 
 /// Unix-only API.
diff --git a/tests/socket.rs b/tests/socket.rs
index f06febbc..e0161bda 100644
--- a/tests/socket.rs
+++ b/tests/socket.rs
@@ -106,6 +106,8 @@ fn protocol_fmt_debug() {
         (Protocol::ICMPV6, "IPPROTO_ICMPV6"),
         (Protocol::TCP, "IPPROTO_TCP"),
         (Protocol::UDP, "IPPROTO_UDP"),
+        #[cfg(target_os = "linux")]
+        (Protocol::MPTCP, "IPPROTO_MPTCP"),
         (500.into(), "500"),
     ];