Robert Julien Mongrain (born August 31, 1959) is a Canadian former professional ice hockey centre. He played in the National Hockey League with the Buffalo Sabres and Los Angeles Kings between 1979 and 1986. The rest of his career, which lasted from 1979 to 1994, was spent in the minor leagues and then in the Swiss Nationalliga A. After his playing career Mongrain became a coach in the Quebec Major Junior Hockey League, Canadian university leagues, and in Switzerland. In his NHL career, Mongrain appeared in 81 games. He scored thirteen goals and added fourteen assists.