Robert Julien Mongrain (born August 31, 1959 in La Sarre, Quebec) is a former professional ice hockey centre. He played in the National Hockey League with the Buffalo Sabres and Los Angeles Kings. He played Junior "A" hockey for the Cap de la Madeleine Barons and major junior for the Trois-Rivières Draveurs. Undrafted by an NHL team, Mongrain was signed as a free agent by the Buffalo Sabres in 1979. Over the next five seasons he split his career between the Sabres and the Rochester Americans, winning the Calder Cup in 1983 with the Americans.