Kabhi Khushi Kabhie Gham... (Sometimes Happiness, Sometimes Sadness), also known by the initials K3G, is a 2001 Hindi-language family drama film written and directed by Karan Johar and produced by Yash Johar under his banner Dharma Productions. The film has an ensemble cast, starring Amitabh Bachchan, Jaya Bachchan, Shah Rukh Khan, Kajol, Hrithik Roshan, and Kareena Kapoor, with Rani Mukerji in an extended guest appearance. It tells the story of an Indian multimillionaire family, which faces troubles and misunderstandings over their adopted son's marriage to a girl belonging to a lower socio-economic group than them. The film score was composed by Babloo Chakravarty with the music composed by Jatin–Lalit, Sandesh Shandilya and Aadesh Shrivastava and lyrics written by Sameer and Anil Pandey.

Development began in 1998, soon after the release of Johar's debut film Kuch Kuch Hota Hai (1998). Principal photography began on 16 October 2000 in Mumbai and continued in London and Egypt. Kabhi Khushi Kabhie Gham... was promoted with the tag-line "It's All About Loving Your Parents". Initially scheduled for the Diwali festivities of 2001, the film was eventually released in India, the United Kingdom and North America on 14 December 2001.

Produced on a budget of ₹300–400 million ($6.36–8.48 million), making it the most expensive Indian film at that point, Kabhi Khushi Kabhie Gham... emerged as a major commercial success, both domestically and internationally, with a lifetime gross of ₹1.36 billion ($29 million) at the worldwide box office becoming one of the highest grossing Indian films. It received mixed reviews from critics, with praise for the cinematography, costume design, soundtrack, performances, emotional sequences and themes, but criticised the length and the script. Internationally, it was the highest-grossing Indian film ever, until Johar's next directorial Kabhi Alvida Naa Kehna (2006). Kabhi Khushi Kabhie Gham... won several awards at popular award ceremonies the following year, including five Filmfare Awards and seven IIFA Awards.