Mrs. Puff is one of the main characters in SpongeBob SquarePants, voiced by Mary Jo Catlett. She is SpongeBob's teacher at Boating School, an underwater driver's education course in the town of Bikini Bottom. At her school, Mrs. Puff teaches students how to drive boats like cars. She is a paranoid old pufferfish who wears a sailor outfit and can puff up when she is scared.
Mrs. Puff is a peach-colored pufferfish with teal-colored fins and spines on her back. She has a blonde hairpiece. Her main outfit is a sailor outfit consisting of a blue collared shirt, a yellow string tie, a red skirt, red heeled shoes, and a blue sailor's cap.
Mrs. Puff makes a living by teaching other sea creatures how to drive boats. She is the owner of the only boating school under the sea, Mrs. Puff's Boating School. Her schoolyard has a small classroom building, a sunken lighthouse, a test-driving track with all kinds of stunt ramps, and a nautical surrounding fence with buoys. Most of the time, she teaches her students inside the classroom and only goes outside to the testing course when it is time for the final exam. In addition to giving lectures, Mrs. Puff is known to assign essays for homework and take her class on field trips to boating monuments or stoplights.
Mrs. Puff loves her job except for one thing: SpongeBob's relentlessly reckless driving. He is her most dedicated, enthusiastic student and knows all about the rules of the road, but he always freaks out and crashes when he has to get behind the wheel of a boatmobile. Whenever SpongeBob crashes a boat with Mrs. Puff inside, she puffs up like a car airbag. His driving is so bad that it can cause townwide destruction. Since Mrs. Puff takes all the responsibility for SpongeBob's actions as if she were his mother, she has ended up in jail many times due to his bad driving skills.
A running gag in the series is Mrs. Puff's dubious past and history of mental instability. It is known that she has had to move from another town and start a new boating school under a new name. At one point, she even took up bank robbery as an occupation. She does not like to talk about it, but Mrs. Puff used to have a husband named Mr. Puff. He was turned into a novelty lamp by human scuba divers. Since then, she has formed a new romantic relationship with Mr. Krabs. She has gone on many dates with him, and as of season 10, they have been dating for sixteen years.
- In the alternate universe in the book Once Upon a SpongeBob, she is SpongeBob's mom.
- No other pufferfish have ever appeared in cartoon form on the show, making her unique.
- Some international dubs change her name to use the honorific for an unmarried woman (the equivalent of calling her Ms. Puff).
- In "Pest of the West," her western ancestor Polene Puff is one of the main residents who helps SpongeBob's ancestor SpongeBuck save the town from Dead Eye Plankton.
- Her monologue in "No Free Rides" implies that Mrs. Puff is not her real name.
- According to the DK guide book, Mrs. Puff's school is the biggest establishment in town and it is located in the center of Bikini Bottom.