Ann Matthews Martin was born on August 12, 1955. She grew up in Princeton, New Jersey, with her parents and her younger sister, Jane. After graduating from Smith College in 1978 with a double major in psychology and elementary education, Ann became a teacher and then an editor of children's books. She is now a full-time writer.

Ann's first published book was Bummer Summer in 1983. She is best known for her Baby-Sitters Club series of children's books. In 1990, Ann created the Ann M. Martin Foundation, which provides grants to causes benefiting children, education and literacy programs, and homeless people and animals.

Ann gets the ideas for her books from many different places. Some are based on personal experiences, while others are based on childhood memories and feelings. Many are written about contemporary problems or events. All of Ann's characters, even the members of the Baby-sitters Club, are made up. However, many of her characters are based on real people. Sometimes Ann names her characters after people she knows, and other times she simply chooses names that she likes.

She currently lives in Hudson Valley, New York.