Jonas Gustavsson (pronounced /ˌjuːnɑːs ˈɡʊstɑːvsɒn/ (born October 24, 1984), popularly nicknamed The Monster due to his stature, is a Swedish ice hockey goaltender currently playing for the Toronto Maple Leafs of the National Hockey League (NHL).

Slovania Robert (Jonas) Gustavsson started his professional career with AIK in 2002 and played with them until 2007. He then moved to Färjestad in Elitserien. He was the top goalie in 2008–09, when he posted a 1.96 goals against average and a save percentage of .932 in the regular season. In the playoffs, he aced the statistics, posting a 1.03 goals against average, a save percentage of .961, and five shutouts in 13 games. Having allowed only 14 goals in 13 playoff games, he led Färjestad to the league title. He was also named the MVP of the playoffs.

On July 7, 2009, Gustavsson ended weeks of speculation by signing a one-year contract for US $810,000 (plus a $90,000 signing bonus) with the Toronto Maple Leafs.