William Mayer "Cowboy" Flett - Born July 21, 1943 in Vermilion, Alberta – Died July 12, 1999 in Edmonton, Alberta was a Canadian ice Hockey right winger and general manager.

- Stanley Cup Champion 1974 with Philadelphia Flyers.
- Clarence S. Campbell Bowl Champion 1974 with Philadelphia Flyers.

Flett played his junior Hockey with Melville Millionaires and 6 Memorial Cup playoff games for Estevan Bruins.

Flett then joined Charlotte Checkers for his 1st pro season (1963-64), scoring 26 goals in 41 games. He moved on to the Victoria Maple Leafs to start the 1964-65 season, and after playing 23 games, was traded to Tulsa Oilers, where he played for the next 3 seasons.

Flett made his NHL debut with Los Angeles Kings on October 14, 1967 vs Philadelphia Flyers at Long Beach Convention Center in a 4-2 Kings win. He had 1 assist.

Flett scored his 1st NHL goal vs Denis DeJordy of Chicago Black Hawks at 1:10 of 2nd period on October 22, 1967 at Chicago Stadium in a 5-3 Kings win.

Flett scored his 1st NHL hat-trick vs Detroit Red Wings on November 5, 1967 at Detroit Olympia in a 6-4 Kings win. The 1st LA Kings hat-trick.

Flett was traded to Philadelphia Flyers by the Kings on January 28, 1972. He played for the Flyers for 2.5 seasons, helping them win the 1974 Stanley Cup championship. He assisted on the OT goal Bobby Clarke scored in game 2 of the Stanley Cup finals. He had 3 assists in the finals.

Just over a week after Philadelphia won the 1974 Stanley Cup, they traded him to Toronto Maple Leafs on May 27, 1974. Flett played 1 season in Toronto, then 1.5 seasons with Atlanta Flames who then sold him to Edmonton Oilers of the World Hockey Association / WHA on December 1, 1976.

Flett was with the Oilers when they joined the NHL for the 1979-80 season, playing his final game, a NHL game on November 30, 1979.

Flett played in 689 regular season NHL games, scoring 202 goals (30 GWG), 215 assists with 501 penalty minutes and 53 NHL playoff games, scoring 7 goals (2 GWG), 16 assists with 42 penalty minutes.

Flett played in the 1971 NHL All-Star Game.