McCulloch's time as a Brentford player came to an end in May 1979 when he was persuaded to join Third Division Sheffield Wednesday. Wednesday manager Jack Charlton was looking for a target man to partner Terry Curran in The Owls forward line and saw McCulloch as the ideal man. Charlton was working as a pundit for ITV on the 1979 FA Cup Final and met McCulloch on the Wembley gantry and agreed a deal which went through officially the following month. Jack Charlton, who had a tendency to get mixed up over his player's names often referred to McCulloch as "Ian", confusing him with Notts County's Scottish winger Iain McCulloch. The McCulloch-Curran partnership contributed 34 goals in the following 1979–80 season as Wednesday were promoted.