Mackenzie Elizabeth Arnold is an Australian professional soccer player. She plays as a goalkeeper for National Women's Soccer League club Portland Thorns FC, and for the Matildas, Australia's national women's team. She previously played for West Ham United in England's Women's Super League as well as Brisbane Roar, Perth Glory, Western Sydney Wanderers, and Canberra United in Australia's W-League and Arna-Bjørnar in Norway's Toppserien.