diff --git a/tcpip/tcpip.go b/tcpip/tcpip.go
index c2635d9..aeba76c 100644
--- a/tcpip/tcpip.go
+++ b/tcpip/tcpip.go
@@ -497,6 +497,10 @@
 // the given interface address.
 type RemoveMembershipOption MembershipOption
 
+// OutOfBandInlineOption is used by SetSockOpt/GetSockOpt to specify whether
+// TCP out-of-band data is delivered along with the normal in-band data.
+type OutOfBandInlineOption int
+
 // Route is a row in the routing table. It specifies through which NIC (and
 // gateway) sets of packets should be routed. A row is considered viable if the
 // masked target address matches the destination adddress in the row.
diff --git a/tcpip/transport/tcp/endpoint.go b/tcpip/transport/tcp/endpoint.go
index cc4915d..503b86a 100644
--- a/tcpip/transport/tcp/endpoint.go
+++ b/tcpip/transport/tcp/endpoint.go
@@ -940,6 +940,11 @@
 		e.keepalive.Unlock()
 		return nil
 
+	case *tcpip.OutOfBandInlineOption:
+		// We don't currently support disabling this option.
+		*o = 1
+		return nil
+
 	default:
 		return tcpip.ErrUnknownProtocolOption
 	}