Kuch Kuch Hota Hai is a 1998 Indian Hindi-language musical romantic comedy drama written and directed by Karan Johar and produced by his father Yash Johar under Dharma Productions. It stars Shah Rukh Khan, Kajol, Rani Mukherji, Salman Khan and Sana Saeed. The plot combines two love triangles set years apart. The first half covers friends on a college campus, while the second tells the story of a widower's young daughter who tries to reunite her dad with his old best friend.

Filmed in India, Mauritius, and Scotland, Kuch Kuch Hota Hai was Karan Johar's directorial debut. One of his goals for the film was to set a new level for style in Hindi cinema. The music was composed by Jatin–Lalit, which was the biggest seller of the year.

Kuch Kuch Hota Hai released worldwide on 16 October 1998, coinciding with the Diwali weekend. The film received positive reviews from critics upon release, with high praise for its setting, direction, screenplay, soundtrack, cinematography, cast performances and overall presentation. It was successful in India and abroad, becoming the highest-grossing Indian film of the year and the third highest-grossing Indian film at that time. Outside India, the film was the highest-grossing Hindi film ever until its record was broken by Karan Johar's next directorial, Kabhi Khushi Kabhie Gham... (2001).

Kuch Kuch Hota Hai won various accolades, including the National Film Award for Best Popular Film Providing Wholesome Entertainment and Best Film at the Filmfare Awards, Screen Awards, Zee Cine Awards and Bollywood Movie Awards. The film garnered 8 Filmfare Awards and was the only film to win all four acting awards (Best Actor, Best Actress, Best Supporting Actor, and Best Supporting Actress) until Gully Boy (2019).