Writer: Rajkumar Hirani
Cast: Aamir Khan as Ranchoddas “Rancho” Shamaldas Chanchad / Chhote / Phunsukh Wangdu, one of the titular trio in the engineering college who vanishes after graduation and whom his two friends hunt for ten years while telling stories of their time in college together. Rancho was a prodigal student, with contempt for the inhumanity of the college’s system. At the end of the film, he is shown to be a famous scientist, entrepreneur, and business magnate who also teaches young children when he takes a break from researching.
R. Madhavan as Farhan Qureshi, the film’s narrator and one of the trio whose father persuades him to study engineering over his dream career of wildlife photography; in the end, he is shown to have published several books of photographs.
Sharman Joshi as Raju Rastogi, another of the trio who comes from an impoverished family with a mother who is a retired school teacher and a paralyzed father who worked as a postman. In the flashback story, his family was unable to afford the car that would be demanded as a dowry for his sister. In the present story, he is a settled married man in Delhi who has freed his family from poverty by becoming a wealthy executive.
Kareena Kapoor Khan as Pia Sahastrabuddhe, Virus’ younger daughter, an intelligent and capable doctor. Despite her father’s disapproval, she and Rancho fall in love.
Boman Irani as Dr. Viru Sahastrabuddhe, the college’s strict director known as “Virus” and Pia and Mona’s father who acts as the film’s antagonist. He stubbornly sticks to a doctrinal method of teaching, putting him at odds with Rancho. At the end, he is shown to have changed his doctrinal methods of teaching.
Omi Vaidya as Chatur Ramalingam, a Ugandan-Indian educated in Tamil-speaking Pondicherry who has little knowledge of Hindi, and Rancho’s rival. His habit of being gassy due to consumption of pills to enhance his memorisation earns him the nickname Silencer. In the present story, he is vice-president of an American company (Rockledge Corporation) who discovers his success being overshadowed by Rancho in the end of the film. Baradwaj Rangan wrote that Chatur being a Tamil from Uganda makes him “twice removed from the North Indians around him – a stranger to the nation as well as the national language.”
Rahul Kumar as young Manmohan (nicknamed Millimetre) and Dushyant Wagh as adult Manmohan (Centimetre). As an adolescent, he earns a small living by doing errands for students, such as laundry, finishing assignments, and getting groceries. Rancho persuades him to buy a school uniform and sneak into school to gain an education. Later he becomes an assistant to Rancho/Phunsukh Wangdu in Ladakh.
Mona Singh as Mona Sahastrabuddhe, Pia’s elder sister, and Virus’s first daughter.
Parikshit Sahni as Mr. Qureshi, Farhan’s father, a strict but loving parent who just wants his son to be happy.
Farida Dadi as Mrs. Qureshi, Farhan’s mother, a loving and caring parent.
Amardeep Jha as Mrs. Rastogi, Raju’s mother, a retired schoolteacher, and dedicated mother.
Mukund Bhatt as Mr. Rastogi, Raju’s paralyzed father who used to work as a postman.
Rajendra Patwardhan as Govind, Viru’s personal assistant.
Javed Jaffrey as the real Ranchoddas Shamaldas Chanchad. It is from him that Raju and Farhan learn the truth: Chanchad’s father sponsored an orphaned servant boy called ‘Chhote’, who had demonstrated his intelligence and love of learning, to earn a degree in the real Ranchoddas’s name, while he was in London. He appreciates what Chhote did for him, and tells Raju and Farhan where to find him.
Arun Bali as Shamaldas Chanchad, father of Ranchoddas Shamaldas Chanchad.
Ali Fazal as Joy Lobo, a student with a passion for machines. After Virus tells him that he will not graduate, he commits suicide.
Akhil Mishra as Librarian Dubey.
Rohitash Gaud as (real) Ranchoddas’s servant.
Achyut Potdar as Machine Class Professor
Madhav Vaze as Joy Lobo’s father.
Olivier Sanjay Lafont as Suhas Tandon, Pia’s ex-fiancé, who cares only about money and ostentation.
Jayant Kripalani as a company head who conducts Raju’s job interview.
Atul Tiwari as R.D. Tripathi, Education Minister in Auditorium during Silencer’s speech.
Rajeev Ravindranathan as ragging senior student.
Supriya Shukla as doctor with Pia.
In 1999, students Farhan Qureshi and Raju Rastogi of the prestigious Imperial College of Engineering (ICE) in Delhi struggle to compete within its cutthroat academic culture. Farhan is passionate about wildlife photography but chose to pursue engineering to appease his father, while Raju is simply in need of a career that will rescue his family from poverty. However, their roommate, the eccentric Ranchoddas Shamaldas Chanchad (nicknamed “Rancho”), is genuinely passionate about science and engineering. Rancho gives unorthodox answers in class and frequently clashes with the school’s staff and its director, Viru Sahastrabuddhe (nicknamed “Virus” by its students), since he believes that students should enjoy what they learn, while the school enforces a strict, exam-based teaching model.
Rancho witnesses the effects of ICE’s hyper-competitive academic culture firsthand when a student named Joy Lobo commits suicide after failing to meet a project deadline and being denied graduation by Virus. Rancho confronts Virus about the undue pressure placed on ICE students to succeed, but his rebellious behavior at the school puts a strain on Farhan and Raju’s relationships with their own families. Raju attempts to distance himself from Rancho, but when Raju’s paralyzed father experiences a medical emergency, Rancho saves his life with the help of Virus’ younger daughter Pia, who begins to fall in love with Rancho. At the end of the year, Rancho is shown to have topped the school’s rankings despite his disdain for its academic system, while Farhan and Raju continue to fall behind.
Years later, the group is approaching their graduation and Rancho continues to academically outperform his friends. One night, while severely drunk, the three of them break into Virus’ home for Rancho to confess his feelings for Pia, while the other two urinate on the property. Virus spots them amidst their escape and gives Raju an ultimatum: be expelled himself, or incriminate Rancho and thus have him expelled. A distraught Raju attempts suicide, but recovers due to committed support and care from his friends and family. With newfound perspective on his life, Raju successfully applies for a job, while Farhan receives an apprenticeship offer from his favorite photographer and earns his father’s blessings.
Virus, infuriated at being proven wrong about the trio’s prospects, attempts to sabotage Raju’s chances of success by holding an unfairly difficult exam. With Pia’s help, Rancho and Farhan break into Virus’ office to steal the exam paper; Raju refuses to cheat, but the three of them are nonetheless caught and expelled from ICE by Virus. Pia confronts her father over her brother’s suicide, which was prompted by similar pressure placed on him by Virus to become an engineer at the expense of his own ambitions. That night, during a rainstorm that causes widespread flooding and power outages, Virus’ older daughter Mona – who is pregnant – goes into labor. Unable to drive to a hospital, Rancho and the other students use their engineering knowledge to quickly modify a vacuum cleaner into a ventouse and deliver the baby with the help of Pia over a video call. A grateful Virus acknowledges Rancho as an extraordinary student and revokes the trio’s expulsions. However, on graduation day, Rancho promptly disappears, never to be seen by his friends again.
Ten years later, Raju and Farhan are both successful in their chosen careers: Raju is a married business executive, and Farhan has published several books of photography. Their narcissistic former classmate Chatur, now a wealthy executive in an American company, calls them claiming to know Rancho’s whereabouts in Shimla, and the three of them depart to find him. However, they come upon an entirely different man who nonetheless lives by the name Ranchoddas Shamaldas Chanchad and holds Rancho’s ICE degree. Upon confrontation, the man explains that Rancho was his family’s orphaned servant boy, who displayed a prodigious academic prowess and was tasked with completing the real Ranchoddas’ academics for him, all the way through to earning a degree at ICE. Rancho, who thereby cared far more about learning than about status, returned home and cut off all contact with his friends at ICE, as he had agreed, but told the real Ranchoddas that “two idiots” will inevitably come looking for him one day. Ranchoddas gives them Rancho’s actual address in Ladakh.
Farhan and Raju decide to bring Pia along with them. Chatur protests the detour, as it would jeopardize his planned meeting with an illustrious client named “Phunsukh Wangdu,” a renowned scientist, but the others restrain him at the back of the car. Farhan and Raju infiltrate Pia’s wedding to her shallow, materialistic boyfriend Suhas and bring her with them. Pia is upset at Rancho for leaving without explanation, but longs to see him again and joins the others.
At Rancho’s address in Ladakh, the group is astonished to find a thriving engineering school in the mountains for local children to build their own projects. They learn that Rancho has kept up to date with their careers and reunite with him by a lake. Rancho admits he is still in love with Pia and the two of them decide to marry. Chatur assumes that Rancho is a lowly schoolteacher, but Rancho reveals his real name to be Phunsukh Wangdu, making him the successful client that Chatur has been after. Rancho explains that he simply runs the school as a side venture. The film ends with Farhan reciting Rancho’s motto on success: “Pursue excellence, and success will follow, pants down.”