William Ronald Plager (July 6, 1945 – January 3, 2016) was a Canadian professional ice hockey defenceman.

Before playing in the NHL, Plager played for the Peterborough Petes in Peterborough, Ontario, where he met his wife Donna Hickey.

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.

After retiring from the NHL, Plager returned to Peterborough with wife Donna Plager, sons William Jr., Brett and daughter Dara.

Plager is the brother of former NHL players/coaches Bob Plager and Barclay Plager. Plager retired from hockey and became a manager at Quaker Oats Peterborough plant and was head coach of Atom B/C IceKats, girls hockey teams in the Peterborough Girls Hockey Association.

He died on January 3, 2016.

Transactions

• 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.

Awards and achievements

• AHL Second All-Star Team (1975)