Dear Ex (Chinese: 誰先愛上他的; lit. 'Who Fell in Love with Him First?') is a 2018 Taiwanese drama film directed by Mag Hsu and Hsu Chih-yen, from a screenplay by Lu Shih-yuan and Mag Hsu. It stars Roy Chiu, Hsieh Ying-xuan, Spark Chen, and Joseph Huang. It follows a teenager becoming trapped in the middle of a bitter feud between his willful mother and a free-spirited man, who is both the lover and insurance beneficiary of his recently deceased father.

The film had its world premiere at the 20th Far East Film Festival on 22 April 2018, and was theatrically released in Taiwan on 2 November 2018, by Warner Bros. It received generally positive reviews from critics and was selected as the Taiwanese entry for the Best International Feature Film at the 92nd Academy Awards, but it was not nominated. At the 55th Golden Horse Awards, it earned eight nominations, including Best Feature Film and Best Leading Actor (for Chiu), and won in three categories: Best Leading Actress (for Hsieh), Best Original Film Song (for "Bali Song"), and Best Film Editing. The film also won Best Narrative Feature, Best Actor (for Chiu), Best Actress (for Hsieh), and the Press Award at the 20th Taipei Film Awards.