Michael Richard Weir (born May 12, 1970) is a professional Canadian golfer.

Born in Bright's Grove, Ontario, Canada at the outskirts of the city of Sarnia, he is a professional golfer on the PGA TOUR. He is a graduate of Brigham Young University and lives in Draper, Utah.

His first PGA TOUR win came at the 1999 "Air Canada Championship" in Surrey, British Columbia. The victory made him the first Canadian to win a PGA TOUR event on Canadian soil in 45 years.

On April 13, 2003, he won the Masters golf tournament at Augusta, Georgia, one of the most prestigious golf tournaments in the world.

Mike Weir now has 6 victories on the PGA TOUR:

Mike Weir is the first Canadian to win one of the current major championships (Sandy Sommerville won the U. S. Amateur when it was considered a major tournament). He is also the first left-handed golfer ever to win the Masters and the first left-handed golfer in 40 years to win any of the four major tournaments.

In June 2003, he tied for 3rd at the U.S. Open, the second of the Grand Slam of golf tournaments.