Kal Ho Naa Ho (transl. Tomorrow may never come, pronounced [kəl ɦoː naː ɦoː]), also abbreviated as KHNH, is a 2003 Indian Hindi-language romantic comedy drama film directed by Nikhil Advani in his directorial debut with a story written by Karan Johar with dialogue by Niranjan Iyengar, and produced by Yash Johar. The film stars Jaya Bachchan, Shah Rukh Khan, Saif Ali Khan, and Preity Zinta, with Sushma Seth, Reema Lagoo, Lillete Dubey, and Delnaaz Irani in supporting roles. In the film, Naina Catherine Kapur (Zinta) and Aman Mathur (Shah Rukh Khan) fall in love, but a secret prevents him from reciprocating his feelings and results in a plan to set Naina up with her best friend, Rohit Patel (Saif Ali Khan).

Collaborating with Johar, Shankar–Ehsaan–Loy composed the soundtrack and score. Anil Mehta, Manish Malhotra, and Sharmishta Roy were the cinematographer, costume designer and art director, respectively. Principal photography took place in Toronto, New York City, and Mumbai from January to October 2003. The soundtrack was released on 27 September 2003 to positive reviews; the title song, "It's The Time To Disco", "Kuch To Hua Hai", and "Pretty Woman" were particularly well-received.

Kal Ho Naa Ho was released on 28 November 2003 with the promotional tagline, "A Story of a Lifetime ... In a Heartbeat". The film received positive critical feedback and was commercially successful; it grossed ₹860.9 million (US$18.8 million), and was the highest-grossing Indian film of the year. The film explores non-resident Indians, inter-caste marriage, and homosexuality through innuendo and homosocial bonding. It won two National Film Awards, eight Filmfare Awards, thirteen International Indian Film Academy Awards, six Producers Guild Film Awards, three Screen Awards, and two Zee Cine Awards in 2004.