Three nuns, Sister Michelle (Moore), Sister Barbara (Jane Elliot), and Sister Irene (Barbara McNair), leave their convent and go undercover as laywomen in order to work as nurses for John Carpenter (Presley), an inner-city doctor.
The three work with all kinds of patients, from abused children to elderly heart attack patients. Meanwhile, Michelle and Carpenter (who doesn't know her true vocation) fall for each other, and Michelle is forced to decide whether she loves Carpenter enough to leave the convent for good.
Change of Habit contains examples of:
- Abusive Parents: Julio, one of the patients, has a father who hits him, insults him, and tells him not to talk unless he can do it without stuttering.
- And Starring: Elvis Presley and Mary Tyler Moore in Change of Habit.
- Attempted Rape: Julio breaks into Michelle's apartment with a knife and pins her on the bed. Carpenter hears her screaming, runs in, and punches out the rapist.
- Desk Sweep of Rage: A childhood version. Michelle tries to get the autistic child Amanda to put colored blocks in the appropriate holes. They have some success before Amanda loses patience and sweeps the board off the table.
- Dress Hits Floor: When the nuns change into street clothes, their habits are shown hitting the floor.
- Eyes Always Averted: When Carpenter grabs Amanda's chin, she tries to turn her head away.
- Freeze-Frame Ending: The credits roll over a scene of Carpenter singing to the congregation, which freezes at the end.
- Friendly Address Privileges: Carpenter says that anyone who's worked for him for a week is allowed to call him John.
- Hands-On Approach: Carpenter teaches Michelle how to play guitar by standing behind her, wrapping his arms around her, and putting his hands on hers.
- Hates Being Touched: Amanda resists physical contact.
- Hollywood Autism: The 1960s version, a curable mental illness caused by refrigerator mothers.
- I Have Boobs, You Must Obey!: Barbara convinces some men to help her move furniture into her new apartment by walking down the street in a short dress slipped off her shoulder.
- I Have Brothers: Carpenter asks Michelle how she can play touch football so well.Michelle: I have five brothers.
Carpenter: They taught you to play?
Michelle: No, I taught them to play!
- Innocently Insensitive: Post-cure Amanda hears Irene, the only black nun, talking about her difficult background. Later, when she arrives at a party with a black hand puppet, she announces, "My name is Irene. When little white girls was playing with dolls I was praying I could be somebody and not just another nigger in the streets."
- Loan Shark: Almost everyone in the neighborhood owes money to The Banker, who charges exorbitant interest rates and has his goons violently beat anyone who can't pay up.
- Meaningful Name: Sister Michelle has to choose between serving Jesus Christ and being in love with a man named John Carpenter (note the latter's Significant Monogram and occupational surname).
- Parental Abandonment: Amanda lives with her aunt after her mother, who never wanted her to begin with, abandoned her a few years ago, while her father is never mentioned. Her autism is explained as her hiding behind a "wall of rage" to cope with this.
- The Peeping Tom: Julio spies on Michelle as she gets ready for bed.
- Pun-Based Title: A play on a nun's habit (outfit).
- Security Blanket: Amanda is very attached to her Raggedy Ann doll.
- Speech Impediment: Julio's severe stutter, which Michelle works with him to improve. By the time he tries to rape Michelle, he seems to be mostly over it, although he still doesn't like talking in complete sentences.
- Tantrum Throwing: Amanda throws the first block Michelle gives her across the room.
- The Teetotaler: The nuns, unsurprisingly.
- Then Let Me Be Evil: Julio's attempts at returning the stolen statue only gets him arrested and blamed for breaking it, so he gives up on good and tries to rape Michelle.
- Thief Bag: When Julio sneaks into the church to return the statue he stole, he carries in a sack, presumably the one he stole it in.
- Throwing Off the Disability: Amanda is cured with rage reduction, which supposedly lets her anger out and allows her to interact normally.
- Waving Signs Around: Enraged by a cashier's unfair treatment of Hispanic customers, Barb makes a sign that says "AJAX GROCERIES UNFAIR TO CUSTOMERS" and sits by the counter ranting about it until she's arrested.