Brayden Sier (born 12 December 1997) is a professional Australian rules footballer.
Sier finally broke through at a AFL level in the second half of the 2018 AFL season, when Adam Treloar was sidelined with a serious hamstring injury. Sier debuted in round 15 against the Gold Coast Suns at Carrara Stadium. He averaged 19.5 possessions (including 10.6 contested), four clearances and 4.6 tackles for the year and played in the 2018 AFL Grand Final loss to the West Coast Eagles