Marilyn Singer was born in the Bronx, New York, on October 3, 1948, and lived most of her early life in North Massapequa on Long Island. She attended Queens College, City University of New York as an English major and education student, and for her junior year, attended Reading University, in England. She holds a bachelor's degree in English from Queens and a MA in Communications from New York University. Marilyn Singer had been teaching English in New York City high schools for several years when she began writing in 1974. Initially, she wrote film notes, catalogues, teacher's guides and filmstrips. She also began looking into magazine writing. Her article proposals were not very successful, but she did manage to have some of her poetry published. Then one day she penned a story featuring talking insects she'd made up when she was eight. Encouraged by the responses she got, she wrote more stories and in 1976 her first book, The Dog Who Insisted He Wasn't, was published.
Since then, Marilyn has published more than 50 books for children and young adults. In addition to a rich collection of fiction picture books, Singer has also produced a wide variety of nonfiction works for young readers as well as several poetry volumes in picture book format. Additionally, Singer has edited volumes of short stories for young adult readers, including Stay True: Short Stories for Strong Girls and I Believe in Water: Twelve Brushes with Religion.