The shot-stopper has caught the eye with his displays in the youth ranks at Celtic and with Scotland’s Under-16s and Under-17s.
Celtic have been trying to keep hold of Mahady amid keen interest from clubs south of the border and it appears the Hoops have lost the battle.
The 16-year-old goalkeeper is set to swap Celtic for Premier League side Leeds, where he will look to continue his development.
Leeds have focused on youth in recent seasons, with a number of players progressed from their development squad and into the first team mix.
Losing Mahady will be a blow for Celtic, who believe the goalkeeper has a bright future in the game.
Mahady will look to quickly adapt to life at Elland Road and push through the club’s youth set-up and towards the first team.
The goalkeeper made his Scotland Under-17s bow earlier this year against Sweden, in a 1-0 defeat.