Gillian Sewell (born November 1, 1972 in Belfast, Northern Ireland) is a former Irish Canadian field hockey player who earned 36 international caps for the Canada during her career.
On national level Sewell, a resident of Hamilton, Ontario, has participated in the CIAU Championships for four years and has led her team to three OWIAA Championships. She has been a CIAU and conference all star from 1991-1994 and 1996.
The Belfast-born Sewell claimed all-star honours in Indoor Hockey as well for both Ontario and Canada. She captained the 1993 Canadian Junior World Cup Team.