In 2015, she reunited with director Choi Dong-hoon for "Assassination", an espionage action film set during the 1930s colonial era in which she played a sniper who assembles a squad of independence fighters to kill a Japanese army commander and a pro-Japanese Korean business tycoon. The film was another box-office success for Choi and Jun; "Assassination" was the highest-grossing Korean film of the year as well as the seventh all-time highest-grossing film in Korean cinema history. Jun was awarded Best Actress at the Grand Bell Awards and Max Movie Awards.