Rahul Khanna (Shah Rukh Khan) and tomboy Anjali Sharma (Kajol)are best friends in St. Xavier's College. The college principal Mr. Malhotra (Anupam Kher) has a beautiful daughter Tina (Rani Mukherjee), who comes to St. Xavier's from London to finish her degree. She becomes friends with both Rahul and Anjali. When Anjali realizes that she is in love with Rahul, she is encouraged by her motherly guardian Rifat Bi (Himani Shivpuri) to tell him so. Instead, Anjali is left heartbroken when Rahul tells her that he loves Tina. Anjali decides to leave college and shares a tearful goodbye with Rahul, going away from Rahul and Tina's lives forever. Tina then realizes that she came between two best friends who actually loved each other. After college, Rahul marries Tina and, in a year of marriage, Tina gives birth to a baby girl. Tina has complications in her pregnancy and has little time left, so she writes eight letters to her daughter (one for each of her first eight birthdays), so that she will know her mother. Before dying, Tina asks Rahul to promise her to name their daughter Anjali.
Eight years pass, and Rahul is a single parent living with his daughter and loving mother (Farida Jalal). On her eighth birthday, little Anjali Khanna (Sana Saeed) reads the last and most important letter that her mother left her; it tells the story of Anjali Sharma and how she was always Rahul's true love. Tina explains in her letter that Rahul always said that love is friendship, and without friendship there can be no love. Rahul is a single parent and lacks a friend in his life, so Tina gives her daughter the mission of reuniting Rahul with Anjali Sharma and bringing back Rahul's lost love. Anjali Sharma is no longer the tomboy she was in college; she is now more feminine, and is engaged to Aman Mehra (Salman Khan). However, she explains to her mother (Reema Lagoo) that she does not really love him and is marrying him as a compromise as she feels she can never love again after losing Rahul. Aman also suspects that she does not really love him. Anjali Khanna and her grandmother search for Anjali Sharma and soon learn that she is going to be working at a summer camp. They travel there, with a plan to later lure Rahul to come as well, and the two Anjalis meet each other. One night while watching television, Anjali Sharma realizes she has met her best friend's daughter, and that Tina is dead. Rahul soon arrives at Camp Sunshine, where he and Anjali Sharma are surprised and delighted to see each other again, sharing a sweet reunion. Throughout the days spent at the camp, Rahul and Anjali feel themselves falling in love. However, Anjali remembers that she is engaged and feels guilty. Aman arrives and tells Rahul that he is Anjali's fiancee. Rahul is heartbroken but congratulates Anjali. She takes this as him rejecting her again, so she leaves summer camp and decides to get married to Aman as soon as possible.
After seeing Tina in a dream, Rahul and his family go to Anjali's wedding, where Rahul silently confesses to Anjali that he loves her, and watches in tears as she is brought forth for the wedding. Realizing this, Anjali is hesitant to go on with the marriage, and stands weeping. Aman notices the tears in her eyes and realizes that she has always been in love with Rahul. He releases Anjali from the engagement and tells her to marry Rahul. Rahul and Anjali have an emotional hug and as the two marry, little Anjali has a vision of Tina smiling and giving her the thumbs up.
- Shah Rukh Khan as Rahul Khanna: A student at St. Xavier's college, and Anjali Sharma's best friend. He marries Tina and they name their daughter 'Anjali.'
- Kajol as Anjali Sharma: The college's tomboy and Rahul's best friend, who is secretly in love with him.
- Rani Mukerjee as Tina Malhotra: The principal's daughter, feminine, sophisticated, an alumna from Oxford University. She is the woman with whom Rahul eventually has a daughter, but has always felt guilty for coming between Anjali and Rahul. She passes away after giving birth to her child.
- Salman Khan as Aman Mehra: Anjali Sharma's loving fiancé.
- Sana Saeed as Anjali Khanna: Named after Anjali Sharma, she is Rahul's and Tina's daughter.
- Farida Jalal as Mrs. Khanna: Rahul's mother.
- Anupam Kher as Principal Malhotra: Tina's father. He is slightly infatuated with Ms. Briganza.
- Archana Puran Singh as Ms. Briganza: A showy English teacher. She flirts with Principal Malhotra.
- Reema Lagoo as Mrs. Sharma: She is Anjali Sharma's mother and has doubts about her daughter's motives for marrying Aman.
- Himani Shivpuri as Rifat Bi: St. Xavier's girl's hostel housekeeper.
- Johnny Lever as Col. Almeida: The manager of Camp Sunshine.
- Parzan Dastur as Silent Sardarji: A Sikh boy at Camp Sunshine that never talks.
- Neelam as herself in a special appearance: She is the host of The Neelam Show.
|1||"Kuch Kuch Hota Hai"||Udit Narayan, Alka Yagnik||4:56|
|2||"Koi Mil Gaya"||Udit Narayan, Alka Yagnik, Kavita Krishnamurthy||7:16|
|3||"Saajanji Ghar Aaye"||Kumar Sanu, Alka Yagnik, Kavita Krishnamurthy||7:14|
|4||"Kuch Kuch Hota Hai (Sad)"||Alka Yagnik||1:26|
|5||"Yeh Ladka Hai Deewana"||Udit Narayan, Alka Yagnik||6:36|
|6||"Tujhe Yaad Na Meri Aayee"||Alka Yagnik, Manpreet Akhtar, Udit Narayan||7:03|
|7||"Raghupati Raghav"||Alka Yagnik, Shankar Mahadevan||2:05|
|8||"Ladki Badi Anjaani Hai"||Kumar Sanu, Alka Yagnik||6:23|