Uday Shetty (Nana Patekar) and Majnu Bhai (Anil Kapoor) end a life of crime and become honest businessmen, settling in Dubai. Two conwomen from India, Poonam (Dimple Kapadia) and Babita (Ankita Shrivastav), present themselves as Maharani Padmavati and Rajkumari Chandini of Najafgarh in order to con Uday and Majnu of their money. Babita causes the two men to fall in love with her, thus getting them to finance herself and Poonam's luxurious lifestyle. Later, it is revealed that Uday has another sister Ranjana (Shruti Haasan) from his father's third marriage and Majnu and Uday are emotionally blackmailed by Uday's father into arranging the marriage of Ranjana and are also forced to do so as Poonam makes that one of her conditions for getting Babita married to either one of them.
The movie then shifts to Dr. Ghunguroo (Paresh Rawal), who has found out that he has a step son from his wife's previous marriage, Ajju a.k.a. Ajay (John Abraham). Ajju is a local goon of Mumbai, where Ranjana studies. Through a chain of hilarious events, they both fall in love with each other. Meanwhile, Majnu and Uday arrange the marriage of Ranjana with the step-son of Doctor Ghunguroo, not knowing that he is a goon. However, at the engagement ceremony, Majnu reveals the truth of Ajju, to which Ajju resists with a fight, threatening to marry Ranjana without any of the brothers' consent.
In order to keep Ajju at bay, Uday and Majnu visit Wanted Bhai, (Naseeruddin Shah), who is an infamous blind don. They also return to their old, violent ways in order to kill Ajju. The brothers are shocked to find that Wanted's son Honey (Shiney Ahuja) likes Ranjana and would like to marry her. They decide to arrange the marriage of Ranjana to some other decent man, in order to sidestep Ajju as well as Wanted's son. However, due to Ajju and Dr. Ghunguroo, who are in league with Babita and Poonam, they are caught by Wanted Bhai, who summons them to his island.
There, Ajju and Dr. Ghunguroo try to convince Honey that he no longer loves Ranjana and that Babita is his true love. Meanwhile, Uday and Majnu try to kill Ajju, but are frightened at the graveyard in a ghost act planned by Dr. Ghunguroo, Ajju and Ranjana. Unbeknownst to all of them, their activities have been recorded by closed-circuit television, causing Wanted Bhai and Honey to plan to finish them off. However, in a hilarious climax scene, Honey is kidnapped by all of them and they escape towards the desert where they are chased by Wanted Bhai. In the midst of saving himself, Dr. Ghunguroo pushes Wanted Bhai, causing him to faint. Meanwhile, a group of camels heavily march there. Ajju is successful in saving Wanted Bhai from the stampede of camels, and restoring his sight. Wanted Bhai himself, as a form of gratitude, arranges the marriage of Ajju with Ranjana, calling Ajju his 'second son'.Anil Kapoor as Majnu Bhai (Sagar Pandey)
Nana Patekar as Uday Shetty/Shankar Shetty
John Abraham as Ajju Bhai / Ajay Barsi
Shruti Haasan as Ranjana Shetty
Karan Khanna as Karan
Paresh Rawal as Dr. Ghunghroo
Dimple Kapadia as Poonam/Maharani Padmavati
Naseeruddin Shah as Wanted Bhai
Ankita Shrivastav as Babita/Rajkumari Chandini
Shiney Ahuja as Honey (Wanted's son)
Supriya Karnik as Payal, Mrs. Ghunghroo
Radhika Bangia - special appearance in song "20-20"
Sakshi Maggo– special appearance in song "20-20"
Lauren Gottlieb – special appearance in song "20-20"
Reema Debnath – special appearance in song "20-20"
Rajpal Yadav as tailor
Neeraj Vora as Baadshah Bhai
Surveen Chawla and Snigdha Gupta Mehta – cameo appearance in song "Tutti Bole Wedding Di"
Akshay Kumar as Rajiv, in flashback scenes from Welcome
Feroz Khan as Ranvir Dhanraj Xata (known by the acronym RDX), in flashback scenes from Welcome.
A large portion of Welcome Back was shot in the United Arab Emirates. It is the first Bollywood film to be shot inside the Emirates Palace in Abu Dhabi. Later, a replica of the Emirates Palace was re-created in Mumbai's Film City to shoot the song "Tutti". A comedy sequence was shot at The Meydan, the world's first five-star track-side hotel, situated at the Meydan Racecourse in Dubai. Other filming locations include the Jumeirah Zabeel Saray Hotel, the Waldorf Astoria Dubai Palm Jumeirah, the Sofitel Hotel – The Palm, the Grand Hyatt Hotel, the Burj Khalifa and Rixos The Palm Dubai. A particular scene was shot in Dubai's Margham Desert, with 1000 camels being arranged for it. It was reported that a pivotal scene was shot on the personal yacht of the Royal Family of Dubai, Al Maktoum. Furthermore, it was said that limited edition luxury and sports automobiles including a Ferrari Spider, a Mansory Carbonado Apertos, an Aston Martin One-77 and a Rolls-Royce Phantom were used in the film.
The soundtrack for Welcome Back was composed by seven artists: Meet Bros Anjjan, Anu Malik, Mika Singh (each one song in collaboration with Yo Yo Honey Singh and Milind Gaba, Abhishek Ray and Siddhant Madhav. The lyrics were written by Kumaar and Manoj Muntashir. The music rights for the film were acquired by T-Series. The full audio album was released on 6 August 2015.
Bollywood Hungama gave the film 3.5 stars out of and wrote, "if you enjoy slapstick comedy that defies logic and have enjoyed Welcome, then Welcome Back is surely a paisa vasool entertainer for you". Dhriti Sharma, writing for Zee News, stated, Welcome Back is vibrant and the ensemble cast keeps it gripping. The screenplay is brilliant, just a little bit of loops in editing in the first song. The comic flavour of the movie has been kept intact and the direction has been profoundly beaded into scenes". Ananya Bhattacharya from India Today gave it 3 stars out of 5 and wrote, "Welcome Back is quite the laugh riot that can de-stress you after the atrocities of the week. Leave the brains aside, and you have (at least) two hours of hardcore fun". Rohit Vats from Hindustan Times gave the film 2.5 out of 5 and wrote, "Welcome Back is funny in parts, but that Welcome fluidity is missing big time. There are moments but they are very limited in number. Welcome Back's pace is its biggest asset and that may make you enjoy this 153-minute long film". Deepanjana Pal from Firstpost wrote, "At 153 minutes, Welcome Back is just a shade too long and the ending is a sandstorm of stupidity. But you'll forgive Bazmee and gang because for at least 120 minutes, this comedy keeps you in splits. Welcome Back might be 2015's silliest film and this is the best reason to watch it". Shilpa Jamkhandikar, writing for Reuters, stated, "Welcome Back is sporadically funny, one that ebbs and flows; but it just about passes the 'guilty pleasure' test thanks to Kapoor and Patekar". Filmfare wrote, "watch the film if you like cornball comedies. It's a pure massy, masala entertainer that's good to go on a lazy weekend". Rediff's Raja Sen, while giving the film 2 stars out of 5, wrote, "Welcome Back is dumb yet entertaining, utterly silly but made with a kind of absurd, warm energy". Shubha Shetty-Saha from Mid-day called the film "a blazing example of the 'Leave your brains at home' variety" and "a fun watch which will keep you snorting and giggling even after you exit the theatre".
Shubhra Gupta writing for The Indian Express gave the film 1.5 stars out of 5 and stated, Welcome had a welcome lightness in most of its steps. And it made us laugh. Welcome Back, minus Akshay and Katrina, plus John and Shruti, and Dimple and a new girl, and Naseer and Shiney, clomps about, looking for the laughs. And failing, mostly, to find them". Saibal Chatterjee from NDTV wrote, "nothing that this nonsensical action comedy unleashes, not even the in-form Anil Kapoor-Nana Patekar pair, can compensate for its absence of substance. Welcome Back...is as appealing as a dunk in a garbage dump". Livemint's Uday Bhatia wrote, "Over its cruelly prolonged 150-minute running time, Welcome Back treats human intellect with the sort of disdain that's remarkable even for Bollywood. It's not just that these are old gags; they've been repurposed so lazily that you can see the actors tiring of a scene even as they perform it".
The film has collected an estimated ₹133.26 crore (US$21 million) in 17 days.
On its first day, the film grossed ₹14.35 crore (US$2.2 million), while collecting ₹17.05 crore (US$2.7 million) on its second day and ₹19.60 crore (US$3.1 million) on its third day. Thus, its first weekend's domestic gross stands at ₹51 crore (US$8.0 million). The film collected ₹73.75 crore (US$11 million) in its first week. Welcome Back had ₹11.75 crore (US$1.8 million) nett in its second weekend with a total 10-day collection of ₹85 crore (US$13 million). The film grossed around ₹96 crore (US$15 million) after three weeks and became the fourth highest grosser of the year.
On its first day, the film grossed ₹8 crore (US$1.2 million).On its second day, the film grossed ₹5 crore (US$780,000).On its third day, the film grossed ₹8.38 crore (US$1.3 million).Thus, its first weekend's overseas gross stands at ₹21.38 crore (US$3.3 million). The film has collected $4.25 million plus in the first week. The film collected $1.5 million apprx in gulf and $1 million in US/Canada and around ₹6 crore (US$940,000) nett in its second weekend.
After the success of two films, the makers are planning a third part of this franchise. Reportedly it has been titled Welcome to the Jungle. Producer Firoz Nadiadwala said "It is an all-out action film featuring the army and features some of the most complicated stunts ever filmed in a Hindi movie." Anil Kapoor, Nana Patekar, Akshay Kumar, John Abraham and Paresh Rawal will return for the third instalment.