Sean Grassie is a Canadian curler from Winnipeg, Manitoba. As a junior, Grassie and his rink of , and won the Manitoba Junior Men's Championship in 1999. The team represented Manitoba at the 1999 Canadian Junior Curling Championships, where they finished with a 6-6 record. Grassie and a new mixed rink of , and represented Manitoba at the 2012 Canadian Mixed Curling Championship. Grassie led Manitoba to an 8-5 record, which was not good enough to make the playoffs. Grassie won his first World Curling Tour event at the 2014 Mother Club Fall Curling Classic.