• Rani Mukherjee was not Karan Johar's first choice for the role of Tina. Twinkle Khanna was supposed to play her role. Reportedly she shot for 11 days and waked out of the movie. Other actresses such as Raveena Tandon, Aishwarya Rai Bachchan, Tabu, Urmila Matondkar and Karisma Kapoor were also offered the role of Tina Malhotra, but all of them declined. The role finally went to Rani Mukherjee and the rest is history.
  
• During Neelam Show, the scene just before Shah Rukh Khan speaks, there is a scene in which a guy pleads her girl friend to leave him because he has found a new girl. The guy's role was played by none other than Nikhil Advani who directed Shah Rukh Khan in 'Kal Ho Na Ho' and the new girl was Farah Khan who directed Shah Rukh Khan in 'Main Hoon Naa' and 'Om Shanti Om'.
  
  
• Karan Johar wanted Rani Mukerjee to be dubbed due to her husky voice, not knowing that her voice would become one of the movie highlights and an important part of her powering personality.
  
• The scene in which Kajol walks up to Rani and Shah Rukh Khan dressed up in a pink and orange dress, is laughed at by none other than Bollywood choreographer Farah Khan and Fashion Designer Manish Malhotra sitting on the stairs. Farah Khan wears a cap and Manish is seen sitting right next to her.

Farah Khan and Manish Malhotra in one of the scenes in Kuch Kuch Hota Hai

• There is a bike riding sequence in one of the songs in the movie where Kajol lost control of the bike(cycle) and cut her knee quite badly. You can see her losing control before the camera cuts out the shot. Kajol hit the ground hard and actually lost consciousness for several minutes.

• During the first basketball game, we see Shah Rukh Khan and Kajol "supposedly" jumping high in the air to shoot a basket. The hoop was actually a bit low, and they used trampolines to jump.

• The scene at the end of the song "Ladki Badi Anjaani Hai" where Kajol's Saree flies in the air and Shah Rukh Khan realizes her love for her, was not originally in the script. It was chroregrapher Farah Khan who added it impromptu, believing it will add a filmy touch to the scene and it sure did :)

• The famous dialogue "Tussi jaa rahe ho?Tussi na jao" from movie was dubbed by 'kaivalya chheda' in absence of the actual child artist.

• Aamir Khan turned down the role of Aman Mehra because he didn't want to be overshadowed by Shah Rukh Khan. Ajay Devgan was also offered the role Aman Mehra but he also declined it

• Actress Rani Mukerji and Kajol are cousins in real life.

• Karan Johar had approached Javed Akhtar to write the songs of his film, but Javed Akhtar declined it because he was uncomfortable with the tittle.

• In the song "tujhe yaad na meri aayi" Choregrapher Gita Kapoor has done the cameo. She is popularly known as Geeta Maa and appeared as a judge in Dance India Dance.
  
• Kuch Kuch Hota Hai won 2 National Film Award, one for Best Film For Providing Wholesome Entertainment and the other for Best Female Playback Singer (won by Alka Yagnik).

• In the 44th Filmfare Awards, Kuch Kuch Hota Hai won 8 major awards and they were for: Best Film, Best Director, Best Actor, Best Actress, Best Supporting Actor, Best Supporting Actress, Best Art Direction and Best Screenplay.