Plot Summary

MAMA'S BOY centers on 29-year-old Jeffrey (Jon Heder), a man with no intention of growing up, who still lives comfortably with his mother Jan (Diane Keaton). Perfectly content with the pampered life she provides, Jeffrey shows no desire to give up this childlike existence.

This “five-star hotel” lifestyle is suddenly threatened when Jan meets the charming and confident Mert (Jeff Daniels). Sweeping Jan off her feet, Mert soon moves into their home, disrupting the delicate balance of the mother–son relationship. Feeling his privileged position slipping away, Jeffrey plots to sabotage the romance.

To execute his plan, Jeffrey enlists the help of Nora (Anna Faris), a beautiful waitress and aspiring guitarist. As Jeffrey schemes to undermine his mother’s relationship, a hilariously awkward rivalry develops between him and the would-be stepfather.

As the competition escalates, unexpected emotional shifts begin to take place. Beneath the comedy, MAMA'S BOY quietly traces Jeffrey’s reluctant journey toward maturity, revealing how jealousy, love, and fear of change can ultimately force even the most stubborn man-child to confront adulthood.