She has black hair and is dressed in a purple matchbox dress with matching sleeveless pantalettes with purple high heels and wears a pearl necklace. She resembles a sea sponge, whereas her son resembles more of a kitchen sponge.
She was born as Margaret BubbleBottom to Mr. and Mrs. BubbleBottom. Margaret may have had a sibling.
She married Harold SquarePants and changed her name to Margaret SquarePants.
She had one child, named SpongeBob SquarePants.
She once told SpongeBob to never run with a broom.
She always told SpongeBob not to look for trouble.
She now lives only with her husband since SpongeBob moved out.
In "Whelk Attack," it is revealed that her maiden name is "BubbleBottom." It is also revealed in "A SquarePants Family Vacation" that her real name is Margaret. She is also mentioned in "Sailor Mouth" when SpongeBob says bad word #11 for the first time and the Janitor asks if he kisses his mother with such a dirty mouth, to which SpongeBob responds "Sometimes, but not recently."
Oddly, the Q&A section of the official SpongeBob SquarePants website for New Zealand states that her name is "Claire Gretchen SquarePants." This however, is false.
In the end credits, she is listed as "Mom," and sometimes "Mother SquarePants."