Prior to his sophomore season, Malenstyn and his teammate Jake Bean were selected to represent Team Canada at the 2015 Ivan Hlinka Memorial Tournament. Malenstyn finished the tournament with three points in five games, including a goal in Canada's 7–3 over Sweden to earn a gold medal. Upon joining the Hitmen for their 2015–16 season, he was named to the National Hockey League’s Players to Watch list for November in advance of the 2016 NHL Draft. By January 2016, Malenstyn was ranked 124th amongst all North American skaters after he recorded 20 points in 44 games. He was later named to Canada men's national under-18 ice hockey team pre-competition roster for the 2016 IIHF World U18 Championships. Malenstyn concluded his sophomore season with 25 points in 70 games and earned the teams' Chrysler Canada Inc. Scholastic Player Award.