Ryan Choi is a superhero appearing in American comic books published by DC Comics. Created by Gail Simone and Grant Morrison, the character first appeared in DCU: Brave New World #1 (August 2006) as the third superhero character to use the Atom name in the DC Universe. He emigrated to the United States following the death of his mother, to take up his idol Ray Palmer's former position at Ivy University. He went on to become a member of the Justice League. In the DC Extended Universe film Justice League (2017), Ryan Choi was portrayed by Zheng Kai, but his scenes were cut from the theatrical version. His appearance was restored for the 2021 director's cut of the film, Zack Snyder's Justice League. Osric Chau portrayed Ryan Choi in the Arrowverse crossover "Crisis on Infinite Earths" and The Flash's eighth season.