The 18-year-olds have come through the club’s academy system and seen their progress rewarded.
Tanner, who comes from Blackpool, has represented England up to Under-18 level and has been converted from winger to full-back.
Manchester-born defender Dunne joined the club in 2014 and has signed his first pro deal.
Angel Gomes, Aidan Barlow, Aliou Traore and Arnau Puigmal have all recently signed contracts.
