Rancho, played by Aamir Khan, questions in the film how people first study engineering, then management, and become bankers: 'So what is the point of studying engineering?' This is exactly what Chetan Bhagat (author of 'Five Point Someone', the book the film is adapted from) did: he studied engineering at IIT, management at IIM, and became a banker.
The film had a social impact on attitudes toward education in India.
The film features the real inventions of little-known people in India's backyards: student Remya Jose from Kerala (pedal-powered washing machine), barber Mohammad Idris from Hasanpur Kalan in Uttar Pradesh (bicycle-powered horse clipping machine) and painter Jahangir Painter from Maharashtra (scooter-powered flour mill).
With every eccentric idea of Rancho's, a high-pitched sound is heard in the background.
The wall that Chaturthi urinates on was painted by the Druk Padma Karpo school in Leh and named the 'Rancho Wall'; it has become a popular photo spot for tourists.
The college is named 'Imperial College of Engineering', which is actually the former name of today's Indian Institute of Technology - Delhi.
The character Phunsukh Wangdu is said to be inspired by engineer Sonam Wangchuk from Leh.
When Virus asks on the first day of school who wants to win the pen, Rancho is the only character who does not raise his hand, and in the end he wins the pen.
The film's only romantic song, 'Zoobie Doobi', is a tribute to 'Pyaar Hua ikraar huwa' from Raj Kapoor's 'Shree 420'. Aamir Khan and Kareena (Raj Kapoor's granddaughter) take the place of Raj Kapoor and Nargis; in this song, Kareena sheds the unglamorous look she maintains throughout the film.
In 2010, a 10th-grade student in the Dewas region of Madhya Pradesh wrote 'I QUIT' in his notebook, imitating the suicide scene of Joy Lobo in the film due to homework pressure, and died two days later.
Viru's lesson on space pen technology and Rancho's question of why pencils are not used are based on the urban legend that NASA spent millions of dollars on an astronaut pen while the Soviets used pencils; this legend is false.
Deception is one of the film's main themes. Not only does Chhote impersonate Ranchoddas, but the main characters also resort to various tricks: Farhan fakes a heart attack to meet Chatur; Raju takes the groom's place at Pia's wedding; Chhote tells Raju the lie that his father has recovered from paralysis; Farhan shows over a webcam that the expulsion order has been cancelled to bring Raju out of his catatonic state; and neither Chatur nor the audience learns until the end of the film that Phunsukh Wangdu is actually Chhote. The idea of using deception to overcome life's difficulties is summed up in the song lyrics: 'My heart is afraid of everything / Put your hand on it and caress it / Convince the foolish heart with love'.
In her article published in Economic and Political Weekly, Latika Gupta states that the film has serious problems from a gender perspective: it continues the tendency, which began with the 2007 film 'Jab We Met', of using women's sexual vulnerability for sensation and humour. In one scene, students, professors and the chief guest burst into laughter upon hearing a speech in which the word 'balatkar' (rape) is used 21 times and the word 'stan' (breast) four times.
Just as in 'Taare Zameen Par', Aamir Khan's character Rancho gives Farhan's family the message that they should let their son pursue his passion for photography; in TZP he does the same with Ishaan's family regarding his passion for drawing.
The film includes real Indian inventions by Remya Jose, Mohammad Idris, Jahangir Painter and Sonam Wangchuk.
Throughout the film, it is never stated which branch of engineering Rancho, Farhan, Raju and Chatur are pursuing their undergraduate degrees in.
While informing the students about job placements, Boman Irani says that everyone knows Neil Armstrong because he was the first person to set foot on the moon, but no one remembers the second. This statement is untrue: Edwin Aldrin, who set foot on the moon after Armstrong, is a figure known in aviation circles and has served as a consultant on US government space projects; he is also a cultural icon because the name of Buzz Lightyear, the hero of Disney's TOY STORY series, is derived from Aldrin's nickname 'Buzz'.
In Golmal (2006), Sharman Joshi plays a student staying in the dormitory; the walls of his room are covered with posters of scantily clad women. In 3 Idiots (2009), Sharman Joshi (Raju) is seen praying to God, and later he is mocked that although he prays now, in time he will hang nude posters of women on his room walls. This is a reference to Golmal.
In one scene, while Raju is drunk, he sings the song 'Kuch Na Kaho' from the film '1942: A Love Story', produced by Vidhu Vinod Chopra.
A film titled 'All Is Well', which takes its name from the song in this film, was released in 2015; Kareena Kapoor's uncle Rishi Kapoor appears in this film.
In Hirani's films, a line of dialogue turns into a slogan that sums up the spirit of the film. In 3 Idiots 'All is well', in Munna Bhai MBBS 'Jadu ki Jhappi', in Lage Raho 'Gandhigiri' and in PK 'Wrong Number' are links in this tradition.
While Sharman Joshi and R. Madhavan follow Aamir Khan's trail, they accuse Javed Jeffrey of stealing high-risk projects using his friends' diplomas. Yet in India, tenders are awarded based on a firm's past performance; a diploma only matters in external audits. Moreover, the film says that Jeffrey, the real Ranchoddas Chanchad, was too stupid to pass exams; with that intelligence, winning government tenders would be impossible.
Although the film is adapted from Chetan Bhagat's novel Five Point Someone, Professor Viru Sahastrabuddhe, played by Boman Irani, was inspired by Nurse Ratched in One Flew Over the Cuckoo's Nest. Both are authoritarian, hostile to free thought, and use their positions for blackmail. But while Ratched wins through fear, Virus softens with Rancho's help at his grandchild's birth and abandons his rigid stance on education.
The character played by Omi Vaidya addresses Minister of Human Resource Development R.B. Tripathi in his Teachers' Day speech. This name may be a nod to the famous mathematics professor R.B. Tripathi, who wrote textbooks for engineering exams.
In the scene where Aamir Khan writes two words on the blackboard, the book in his hand is G.H.F. Nayler's Dictionary of Mechanical Engineering.
The film is known in China as 'San Geshagua' (Three Idiots).
This is Rajkumar Hirani's only film in which the main antagonist also wins thanks to the hero. In his previous films, the antagonist (Boman Irani) accepts defeat, but here Virus searches for the perfect student to whom he can pass on the 'Astronaut Pen' given by the dean. When Rancho delivers Mona's baby, Virus finds the perfect student in Rancho.