NAUGHTY @ 40 tells the story of a 40-year-old man [Govinda] living in London with his parents [Anupam Kher, Smita Jaykar] and cousin [Harish]. He has a major problem....he's still a virgin. The father seeks the help of one of his employee [Shakti Kapoor], who tries every trick in the book to help Govinda loses his virginity, but to no avail.
The family goes to Manali, where Govinda gets married to a girl much younger to him [Yuvika Choudhary]. Yuvika is childish and pulls pranks all the time. As a result Govinda gets into a physical relationship with a foreigner. Yuvika gets a rude shock when she discovers the truth. This brings about a change in her attitude.