William Ronald Plager (born July 6, 1945 in Kapuskasing, Ontario) is a retired Canadian ice hockey defenceman.
Plager started his National Hockey League career with the Minnesota North Stars in 1967. He also played for the St. Louis Blues and Atlanta Flames. He left the NHL after the 1976 season.
Bill Plager is the brother of former NHL players/coaches Bob Plager and Barclay Plager
- Traded to Minnesota by Montreal with the rights to Barrie Meissner and Leo Thiffault for Bryan Watson, June 6, 1967.
- Claimed by NY Rangers from Minnesota in Intra-League Draft, June 12, 1968.
- Traded to St. Louis by NY Rangers with Camille Henry and Robbie Irons for Don Caley and Wayne Rivers, June 13, 1968.
- Claimed by Atlanta from St. Louis in Expansion Draft, June 6, 1972.
- Claimed by Minnesota from Atlanta in Intra-League Draft, June 12, 1973.
- AHL Second All-Star Team (1975)