Ian "Bull" Turnbull (born December 22, 1953) is a Canadian former professional ice hockey defenceman who played ten seasons in the National Hockey League from 1973–74 until 1982–83. He and Börje Salming combined to make one of the best 1–2 defensive punches in Toronto Maple Leafs history during the 1970s.
Turnbull played 628 career NHL games, scoring 123 goals and 317 assists for 440 points. In his best offensive season, (1976–77 while with the Maple Leafs), he set career highs with 22 goals, 57 assists, 79 points, and a +47 plus/minus rating. The 79 points still stands over 40 years later as the Maple Leaf team record for most points in a season by a defenceman. He also still holds the NHL record for most goals in a game by a defenceman, with 5 in a game on February 2, 1977, in a 9–1 victory against the Detroit Red Wings. Turnbull only had five shots in the game, making him the first player in NHL history to score five goals on five shots. Turnbull was outstanding in the 1978 playoff series against the New York Islanders, eventually won by Toronto 4 games to 3, anchoring the team’s defensive corps after an eye injury forced all-star defenceman Börje Salming out of the Maple Leafs line-up.
Early in the 1981-82 season, Turnbull was traded to the Los Angeles Kings in exchange for veteran forward Billy Harris and defenseman John Gibson. Turnbull's time with the Kings was brief, playing just 42-games, but one of them was quite memorable. On December 12th, 1981 Turnbull scored four-goals in a 7-5 Kings victory over the Vancouver Canucks.
Turnbull joined the Penguins for the 1982-83 season but played just six games for them before a back injury forced him out of the lineup and into retirement.
Turnbull is currently the IT Director at Martin Chevrolet in Torrance, California, United States.