My Sassy Girl (Korean: 엽기적인 그녀; RR: Yeopgijeogin geunyeo; lit. That Bizarre Girl) is a 2001 South Korean romantic comedy film directed by Kwak Jae-yong, starring Jun Ji-hyun and Cha Tae-hyun. The film is based on a true story told in a series of blog posts written by Kim Ho-sik, who later adapted them into a fictional novel.

The film was very successful in South Korea, where it was the highest-grossing comedy of all time, and one of the top five highest-grossing films ever at the time. When My Sassy Girl was released across East Asia, it became a blockbuster in the region, becoming a hit in Japan, Taiwan and Hong Kong. The film's success in Asia drew comparisons to Titanic. Its DVD release also drew a large international cult following, particularly in China, Southeast Asia, and parts of South Asia. My Sassy Girl sparked an international breakthrough for Korean cinema, and it played a key role in the spread of the Korean Wave.

The film has spawned an international media franchise, consisting of film remakes and television adaptations in different countries as well as a sequel. An American remake, starring Jesse Bradford and Elisha Cuthbert, and directed by Yann Samuell, was released in 2008. A Japanese drama adaptation with Tsuyoshi Kusanagi and actress Rena Tanaka as the leads started broadcasting in April 2008. A sequel, My New Sassy Girl, a collaborative work between Korea and China, was released in 2016. My Sassy Girl has received numerous remakes and adaptations, including Japanese and Korean television adaptations as well as a number of remakes from other countries (American, Indian, Chinese, Nepali, Lithuanian, Indonesian and Philippine versions).