Luka Kovač is a fictional character from the NBC television series ER. The role was portrayed by Goran Višnjić from the sixth season episode, "Leave It to Weaver", which aired on September 30, 1999 until the thirteenth season episode, "The Honeymoon Is Over", which aired on May 17, 2007.

ER is an American medical drama television series created by Michael Crichton that aired on NBC from September 19, 1994, to April 2, 2009, with a total of 331 episodes spanning 15 seasons. It was produced by Constant c Productions and Amblin Television, in association with Warner Bros. Television. ER follows the inner life of the emergency room (ER) of Cook County General Hospital in Chicago, and various critical issues faced by the department's physicians and staff.