diff --git a/pkg/tcpip/header/eth.go b/pkg/tcpip/header/eth.go
index c29d930bf..d45757308 100644
--- a/pkg/tcpip/header/eth.go
+++ b/pkg/tcpip/header/eth.go
@@ -46,6 +46,9 @@ const (
 	// EthernetMinimumSize is the minimum size of a valid ethernet frame.
 	EthernetMinimumSize = 14
 
+	// EthernetMaximumSize is the maximum size of a valid ethernet frame.
+	EthernetMaximumSize = 18
+
 	// EthernetAddressSize is the size, in bytes, of an ethernet address.
 	EthernetAddressSize = 6
 
diff --git a/pkg/tcpip/header/tcp.go b/pkg/tcpip/header/tcp.go
index 709a43d1e..cb9257ad6 100644
--- a/pkg/tcpip/header/tcp.go
+++ b/pkg/tcpip/header/tcp.go
@@ -216,6 +216,11 @@ const (
 	// TCPHeaderMaximumSize is the maximum header size of a TCP packet.
 	TCPHeaderMaximumSize = TCPMinimumSize + TCPOptionsMaximumSize
 
+	// TCPTotalHeaderMaximumSize is the maximum size of headers from all layers in
+	// a TCP packet. This will need to be updated if we decide to support more
+	// layer 2 protocols or features like IP tunneling.
+	TCPTotalHeaderMaximumSize = TCPHeaderMaximumSize + IPv4MaximumHeaderSize + EthernetMaximumSize
+
 	// TCPProtocolNumber is TCP's transport protocol number.
 	TCPProtocolNumber tcpip.TransportProtocolNumber = 6
 
diff --git a/pkg/tcpip/transport/tcp/snd.go b/pkg/tcpip/transport/tcp/snd.go
index 891c1bed9..78abc07d4 100644
--- a/pkg/tcpip/transport/tcp/snd.go
+++ b/pkg/tcpip/transport/tcp/snd.go
@@ -953,7 +953,7 @@ func (s *sender) postXmit(dataSent bool, shouldScheduleProbe bool) {
 func (s *sender) sendData() {
 	limit := s.MaxPayloadSize
 	if s.gso {
-		limit = int(s.ep.gso.MaxSize - header.TCPHeaderMaximumSize)
+		limit = int(s.ep.gso.MaxSize - header.TCPTotalHeaderMaximumSize - 1)
 	}
 	end := s.SndUna.Add(s.SndWnd)