 In effort to boost chance to make to the Ireland Squad for UEFA Euro 2012, Treacy joined Sheffield Wednesday on loan until the end of the season.Treacy made his Sheffield Wednesday debut two days later, coming on as a substitute for Jermaine Johnson in the 78th minute, in a 1–0 win over Leyton Orient.After making appearance, mostly from coming on the bench, Treacy scored his first Sheffield Wednesday goal, coming from a direct free kick and provided a winning goal, in a 2–1 win over Brentford on 28 April 2012.