After a bank robber escapes from prison, his ex-girlfriend Sherry Pierce (Nia Long) flees with her young son Trent to the home of her grandmother, Hattie Mae Pierce aka Big Momma. Unbeknownst to Sherry, the real Big Momma is out of town and undercover FBI agent Malcolm Turner (Lawrence) has stepped into a Fat Suit to impersonate her. Malcolm and his partner John Maxwell (Paul Giamatti) suspect Sherry has the money from the original robbery, but Malcolm starts to doubt her guilt. Later, Sherry "meets" Malcolm out of disguise, where he introduces himself as a local electrician, giving him a chance to bond with Sherry and her son as a possible romantic partner / father figure. Malcolm is torn between his duty as an agent and his growing feelings for Sherry.
The second film, Big Momma's House 2, has Malcolm galvanized by the murder of an FBI colleague, who was undercover with Tom Fuller (Mark Moses), a former Military Intelligence Specialist now in the private sector and suspected of trying to sell an NSA backdoor on the black market. Since he has officially retired from field work for the sake of his family and his boss won't let him in on the case, he covertly reassumes the Big Momma disguise to become the new nanny at the Fuller residence in Orange County. Turner-as-Big Momma bonds with the Fullers and their three children, while trying to get to the bottom of Tom's involvement.
The second and third films were much Lighter and Softer than the first. Both were critically savaged despite an impressive box office turnout.
The third film replaces the actor who played Trent in the first two films, and has Trent taking on a Fat Suit disguise.
The films contain examples of:
- All Girls Want Bad Boys: Could explain Sherry's attraction to the psychopathic criminal Lester.
- Body Horror: When "Big Momma" awakes from her sleep, her fake breast is resting on her shoulder, which horrifies Sherry, who then points it out.
- Butt-Monkey: John, who seems to always get hurt, either by Malcolm, Big Momma, dogs or foreign bad guys.
- Easily Forgiven: Malcolm, who completely gets off scot free for impersonating Sherry's grandmother. He gets the girl. He even gets her grandmother's blessing!
- Elder Abuse: Nolan's self defense class seems more of an opportunity for him to beat up the old women who volunteer to pretend to be a victim.
- Fat Suit / Disguised in Drag: How Malcolm transforms into Big Momma. Complete with bean bag boobs.
- Male Gaze: Malcolm/Big Momma to Sherry. It is Nia Long.
- Oh, Crap!: When Malcolm is almost exposed after Nolan snatches off his wig during his self defense class. Also, when Sherry catches Lester in Trent's room, reading him ghost stories.
- Ooh, Me Accent's Slipping: Malcolm's elderly woman voice goes from exaggerated to almost nonexistent and in some scenes, he sounds exactly like himself.
- Out-of-Character Alert: A minor one in the first film, where Sherry noticed Big Momma (Malcolm) acts more warmly towards her, since apparently (the real) Big Momma is always rather disapproving towards her, resulting in their estranged relationship. Sherry believes she might have gone senile.
- The Reveal: Done in every movie after Malcolm beats the villain.
- Screaming Birth: Big Momma is a midwife and has to deliver Ritha's baby. Her delivery is less than discreet. Nolan even ends up with a shoe in his mouth.
- Scary Black Man: Sherry's psychotic ex-boyfriend Lester Vesco from the first film. He robs a bank, murdering two people in the process, then escapes prison by murdering the prison doctor and driving out in their car. All before the events of the first film.
- Stepford Smiler: Sherry. Though her life is falling apart, she still manages to stay happy for her son's sake.
- Token White: John.
- Too Dumb to Live: Sherry, who despite saying on a few occasions that her grandmother looks different and also saying Malcolm's eyes look "familiar," doesn't realize that her grandmother is not only not her grandmother but the man she's dating. Also, everyone else who notices that she looks different but thinks nothing of it.