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 debutant Nikhil Advani from a script written by Karan Johar and Niranjan Iyengar, and produced by Yash Johar under Dharma Productions. The film stars Shah Rukh Khan, Saif Ali Khan, and Preity Zinta, with Jaya Bachchan, Sushma Seth, Reema Lagoo, Lillete Dubey, and Delnaaz Irani in supporting roles. Set in New York City, the story follows Naina Catherine Kapur (Zinta) who gradually falls for her visiting neighbour Aman Mathur (Shah Rukh Khan), but a secret prevents Aman from reciprocating his feelings, causing him to set Naina up with her best friend, Rohit Patel (Saif Ali Khan).

Collaborating with Johar in a first, Shankar–Ehsaan–Loy composed the original soundtrack and background score, with Javed Akhtar writing the lyrics. 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. Filming was stalled for around six months due to Shahrukh Khan's illness. 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 Hindi film and 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.