 On December 8, 2015, Dinwiddie was hired by the Calgary Stampeders as the team's QB coach.Under Dinwiddie, Bo Levi Mitchell won CFL Most Outstanding Player twice as the Stampeders reached the Grey Cup in three consecutive years, including winning in 2018.On December 12, 2019, Dinwiddie was named the head coach of the Toronto Argonauts, the 45th in team history.