Nikša Roki (born 8 February 1988) is a Croatian swimmer, who specialized in butterfly and individual medley events.

Leading up to the Games, he managed to dip beneath the FINA B-cut in 2:01.56 (200 m butterfly) and 4:25.28 (400 m individual medley) at the Golden Bear meet in Zagreb.

[3] On the first day of the Games, Roki broke a Croatian record of 4:22.44 to touch the wall first in heat one of the 400 m individual medley, but finished only in twenty-third place.

[4] In the 200 m butterfly, Roki repeated his luck in the evening prelims, as he topped the first heat against India's Rehan Poncha, Peru's Emmanuel Crescimbeni, and Honduras' Javier Hernández Maradiaga, overhauling a sub-2:00 barrier with a new Croatian record on a tech body suit in 1:59.58, nearly two seconds faster than his entry time.

[6] Roki is currently a graduate student at the University of Maryland, College Park and is a teaching assistant for freshman level bioengineering courses.