Gellatly was named to the Capital One Academic All-America second team and to the Beyond Sports Network second team and College Sports Madness All-America third team as a senior. He was a first-team All-Ivy League selection in 2013 after setting Cornell single season receiving records with 91 catches for 1,224 yards to go along with eight touchdowns. He led the league and ranked second nationally in receiving yards per game (122.4) and receptions per game (9.1). Gellatly finished his career ranked second at Cornell in career receptions (194) and receiving yards (2,486) and was fifth in all-purpose yardage (3,766 yards). He had a school-record 10 career 100-yard receiving games and two 200-yard games in his career. Gellatly was a two-time All-Ivy pick and served as a team captain during his senior year.