Her parents are divorced, and she has one sister, Aviva Mlynowski, and an older stepsister.

[2] She graduated with an Honors degree in English literature from McGill University.

After her second novel Fishbowl was published, she moved to New York City to write full-time.

Along with authors Michael Buckley, Julia DeVillers, and Adele Griffin, Mlynowski is a co-founder of OMG BookFest, a book festival geared to middle-grade readers.

[3] Mlynowski married her husband Todd in 2004, and together they have two daughters,[1] Chloe and Anabelle.