John Sebastian Östling (born 2 June 1984 in Onsala, Kungsbacka) is a Swedish sailor, who specialized in two-person dinghy (470) class. He represented Sweden, along with his partner Anton Dahlberg, in two editions of the Olympic Games (2008 and 2012), and has also been training for Royal Swedish Yacht Club (Swedish: Kungliga Svenska Segel Sällskapet) throughout most of his sporting career under his personal coach and mentor Per Frykholm. As of September 2013, Ostling is ranked no. 25 in the world for two-person dinghy class by the International Sailing Federation.