The film starts with a Muslim family watching TV in Sultanpur village, Azad Kashmir, Pakistan and an expectant mother’s (Meher Vij) baby kicks when Shahid Afridi leads Pakistan to victory in an India–Pakistan cricket match. A few years later, the baby has grown up to be a young speech-impaired girl, Shahida (Harshaali Malhotra). Her mother takes her to Hazrat Nizamuddin Auliya’s Dargah in Delhi, India, to pray for her speech to return.
In the middle of the night, right next to the border, the train in which Shahida and her mother were traveling has stopped due to a delay. When everyone is asleep she leaves the train to play with a rabbit she saw hiding in a hole. Unfortunately, the train starts as Shahida is playing with the rabbit. She runs as fast as she can to try and catch it, but, realizing that she cannot, she tearfully watches the train cross through the border and into Pakistan. Lost in India with no way to head back over the border to her home, Shahida boards a freight train, reaching Kurukshetra.
In Kurukshetra, a Brahmin devout Shri Hanuman named Pawan Kumar Chaturvedi, also known as Bajrangi (Salman Khan), is dancing merrily with other worshippers. Shahida spots and follows Bajrangi. He assumes she’s also a Brahmin and has separated from her parents. He buys her a Bajrang Bali pendant to protect her from harm. She continues to follow him, even sitting next him on a bus he enters. On the bus ride to Delhi, Bajrangi quizzes the little girl, and calls her Munni to find out which city she’s from, but she doesn’t respond to any Indian town names. When he is asked by a fellow passenger about how he moved from his hometown of Pratapgarh to Delhi, Bajrangi decides to tell his life story.
Bajrangi tells the story of how he used to be a failure during childhood, and that it took him so many years to pass high school, that his father died of shock when he finally did. He moved to Delhi because it was his father’s last wish that he leave him and stay there with a man named Dayanand (Sharat Saxena), to try and find his own job. He tells the story of how he met a woman named Rasika (Kareena Kapoor) in Delhi; they met when a ticket collector on a bus asked Bajrangi to equally split a note of 10 rupees between Rasika and himself. When they got off the bus he followed her and tried to resolve the situation. Exasperated, Rasika asked him to get change from a stall selling water bottles. While he was getting the change, she ran away.
Bajrangi eventually locates the building where Dayanand lives and finds him holding a wrestling competition there. When Rasika — who also lives in the building — sees Bajrangi with Dayanand, she claimed that he had stalked her there and was harassing her. The other wrestlers grabs Bajrangi and identifies himself as Pawan before being thrown out. Dayanand then has him released and brought to stay in his house. During Bajrangi’s stay, he and Rasika bonds, and eventually falls in love. When Rasika refuses a marriage proposal in favor of Bajrangi, Dayanand said that they would be allowed to marry only under one circumstance; if Bajrangi gets a nice job and buys a nice house within the coming six months. Father Dayanand (Sharat Saxena) makes an oath that he will collect enough money for a house for Rasika and to prove himself a worthy groom. Bajrangi convinces Rasika to let Munni stay with them until they can find her parents. After some time, Bajrangi finally finds out that Munni is Pakistani and Muslim when he witnesses her eating beef at a neighbour’s house. Bajrangi attempts to send Munni home, but realizes that she cannot go without a passport. He strikes a deal with the travel agent and uses the money he has been saving for the house to pay the agent. However, Bajrangi is devastated when he finds that the travel agent has taken Munni to a brothel. He takes Munni back with him trying to find ways to get the young girl to her home on his own. They meet Chand Nawaz (Nawazuddin Siddiqui), a journalist of a Pakistani channel who aids Bajrangi in taking her back home. They visit a Mosque and seeks help from an old man and learms that the place depicted in the photo is in Kashmir. Disguised, they manage to barely escape the clutches of the cops before reaching Kashmir
They then visit another Mosque; Pavan prays to God while Nawaz records his life then on for a report and to create a story about Pavan’s truth and innocence. He then post it and they finally escaped. After watching a video they finally learns that whatever is included is Shahida’s mother who was searching for her in same place that he visited. He asks the bus driver who drives the bus whether he knows about the wherebouts of the woman shown in the video and they come to know that she lives in a village called Sultanpur. En-route, they spots a group of cops. Pavan distracts the cops by luring them into him while Chand Nawaz leads Shahida into her home but unfortunately Pavan gets shot leaving him unconscious. The news posted by Chand Nawaz goes viral and spreads throughout India and Pakistan. A senior officer wanting to arrest and punish Pavan pardons him after learning that his actions are for the welfare of the people and for the pride of Pakistan. Realising this the Pakistani people aids Pavan cross the border. The next day they cheer him up by calling him “Bajrangi Bhaijaan”. Shahida finally succeeds in speaking when Bajrangi is about to leave for India. She calls him back and screams “Jai Shree Ram, Mama” (Hail lord Ram, Uncle). They share a hug and embrace each other before finally saying goodbye and parting ways.