Koi... Mil Gaya (Hindi pronunciation: [ˈkoːi mɪl ɡəjaː] transl. Someone...Has Been Found) is a 2003 Indian Hindi-language science fiction action drama film directed and produced by Rakesh Roshan. It stars Hrithik Roshan, Preity Zinta and Rekha. In addition to writing the story, Rakesh Roshan also wrote the screenplay with Sachin Bhowmick, Honey Irani, and Robin Bhatt. Koi... Mil Gaya focuses on Rohit Mehra, a developmentally disabled man who contacts an extraterrestrial being later named Jadoo with his late father Sanjay's supercomputer. The film follows his relationship with Nisha, Rohit's friend, who falls in love with him.

After the release of the commercially and critically successful romantic film Kaho Naa... Pyaar Hai (2000), Roshan wanted to work again with his son Hrithik on a different type of film. In June 2001, during the 2nd IIFA Awards, he announced the second film when he received the Best Director award for Kaho Naa... Pyaar Hai. Principal photography was shot by Ravi K. Chandran and Sameer Arya from November 2001 to March 2003 on sets built by Sharmishta Roy in Canada, India, and New Zealand. Roshan's brother, Rajesh Roshan, composed the film's soundtrack and background score. American artists Mark Clobe and Craig Mumma spent ₹4 crore (US$470,000) on its visual effects.

Filmed on a budget of ₹25 crore (US$3.0 million), Koi... Mil Gaya was released on 8 August 2003 and was the first instalment of the Krrish franchise. Promoted with the tagline "You Are Not Alone...", it targeted children and parents. It was the second-highest-earning Indian film of the year, grossing ₹82.326 crore (US$9.7 million) worldwide. The film had a positive critical reception, with most of the praise directed at the cast's performances. Two sequels titled Krrish and Krrish 3 were released in 2006 and 2013, respectively. A fourth installment, announced to be released in 2026.

The recipient of several awards, Koi... Mil Gaya won three National Film Awards (including Best Film on Other Social Issues). At the 49th Filmfare Awards, it was nominated in eleven categories and received five awards, including Best Film, Best Director (Rakesh Roshan), and Best Actor and Best Actor (Critics) (Hrithik Roshan). The film won five of its eleven nominations at the 5th IIFA Awards, including Best Director (Rakesh Roshan) and Best Actor (Hrithik Roshan). Considered a milestone of its genre, it is one of the first Indian films featuring aliens. The character of Jadoo became popular and inspired a spin-off series entitled J Bole Toh Jadoo (2004). This film was considered a turning point in Roshan's career after having a few previous consecutive flops which put his film career in jeopardy.

Space Scientist Dr. Sanjay Mehra has created a Supercomputer from which he sends variations of the syllable Om into space, hoping to attract extraterrestrial life. When he receives a response, his colleagues ridicules him. While driving to home, an alien spacecraft appears overhead soon after responding to his signals on his computer. Distracted, he gets into a car accident that kills him in car explosion and injures his pregnant wife, Sonia and their son, Rohit, is born with a developmental disability. Sonia learns that surgery is the only cure, for Rohit's disability, but it could paralyze or kill him. Not wanting to lose her son, she raises him in Kasauli.

Years later, a now grown up Rohit is still a schoolboy, due to his disability and has found friends in six children. A young woman, Nisha, arrives and is initially insensitive to Rohit, because of his childish practical jokes against her and also due to her being unaware about his mental condition. Her friend Raj, who also happens to be Rohit's former classmate and his gang attack Rohit and break his kick scooter; Sonia chides them for assaulting Rohit, saying that he did not intentionally make fun of her and reveals about Rohit's condition to Nisha. Realizing her mistakes, Nisha gifts Rohit a bicycle and introduces him to her parents, who are sympathetic to him. Rohit and Nisha (now friends) find Sanjay's old computer, and Rohit inadvertently summons the aliens. The aliens leave hastily, accidentally leaving a group member behind. Rohit, Nisha, his group, and Sonia befriend the alien, naming him Jadoo and discovers his psychokinetic abilities.

Raj resents Nisha's closeness to Rohit, bullying him and spreading a rumour that Raj and Nisha are getting married. The rumour upsets Nisha and Rohit, who is hurt because he thought Nisha was his girlfriend. Jadoo discovers that Rohit is disabled and uses his powers, derived from sunlight, to enhance Rohit's mental and intellectual ability. The next morning, Rohit has clear vision; a seventh-standard student, he later solves a tenth-standard mathematics problem orally (surprising his mathematics teacher and his school principal) and also answers his computer teacher who always chided him for his disability and accidentally beats up Raj's gang too.

Rohit's physical abilities increase to superhuman levels. Raj's gang challenge Rohit and group to a basketball game. Rohit scores several baskets but Raj's gang begin to cheat; when the sun comes out, Jadoo helps Rohit's group win the game. Rohit confesses his love to Nisha and she reciprocates. Raj's gang confront Rohit's group about the basketball game. While fleeing the group accidentally drops Jadoo. Constable Chelaram Sukhwani sees Jadoo in a bag and calls for backup. Led by Inspector Khurshid Khan, they capture the bag; however, Rohit rescues Jadoo. Confronted by Raj's gang, an angry Rohit overpowers them and the policemen arrive. Jadoo is not in the bag; he had escaped when Chelaram was calling the other police officers.