Margaret SquarePants is the mother of SpongeBob SquarePants, the wife of Harold SquarePants, the daughter-in-law of Grandpa SquarePants and Grandma SquarePants, and also the sister-in-law of Blue SquarePants and Sherm SquarePants.
- Harold SquarePants (husband)
- SpongeBob SquarePants (son)
- Grandpa SquarePants (father-in-law, deceased)
- Grandma SquarePants (mother-in-law)
- Blue SquarePants (brother-in-law)
- Sherm SquarePants (brother-in-law)