Mastizaade starts off with the 'sparkling' introduction of Riteish Deshmukh, a self-confessed 'mastizaada'. Seeing his antics and his magnetism towards the opposite sex, makes the two self-confessed sex maniacs Aditya Chotiya (Vir Das) and Sunny Kele (Tusshar Kapoor) to become his disciples. While Aditya and Sunny get thrown out of an ad agency owned by Vivek Vaswani because of their extremely sexual content in all their ads, they land up starting their own ad agency named 'XXX'. On the other hand, in order to find a solution for their sexual obsessions, they check into a rehabilitation centre that's run by the twin sisters (who are sex addicts themselves) Laila Lele (Sunny Leone) and Lilly Lele (Sunny Leone again). While Laila Lele is modernity personified, Lilly Lele is a girl with simple values, but, stammers while talking. A lucky draw in the rehab centre wins Aditya and Sunny a trip to Pattaya alongwith Laila and Lily. Amidst all this, Aditya and Sunny land up falling in love with Laila and Lilly respectively. The problem is that Lilly Lele is already engaged to Deshpremi (Shaad Randhawa), a wheelchair bound wannabe army man who finds it tough to 'stand' on his feet. Amidst all this, there also exists 'Son-Das' (Suresh Menon), who happens to be the 'stereotypical gay' brother of Lilly and Laila. Situations go topsy-turvy when he starts developing feelings towards Sunny Kele. What happens to Aditya and Sunny in the end, do they get the love of their lives, who ultimately gets Sunny Kele between Lilly Lele and 'Son-Das' and do these 'mastizaades' find a solution to their sexual obsessions is what forms the rest of the film.