Maisy is a British children's book series created by British author Lucy Cousins. Walker Books began publishing the series in the UK in 1990. In the US, the books are published by Candlewick Press.
The series focuses on the everyday experiences of Maisy Mouse and her friends. The books are characterised by their bold graphic illustrations paired with simple, structured storylines.
More than 28 million copies of Maisy books have been sold globally, in 29 different languages. Titles within the series are published in many different formats, including board books, picture books, concept books, interactive books, activity books, and pop-up books.
Lucy Cousins developed the idea for a children's lift-the-flap book during her final year at the Royal College of Art. The story she wrote was about a four to five-year-old girl getting ready to go for a swim. She illustrated the concept in her signature style, bold black outlines and bright blocks of colour. The titular character, Sally, had knitted and hand-sewn clothes. Upon presenting her mockup to the publishing company Walker Books, editor Wendy Boase suggested the book would be more 'fun' with an animal character. Sally was spontaneously replaced by Maisy Mouse, while the rest of the book remained the same and was published under the title Maisy Goes Swimming in 1990.
Cousin draws on a variety of everyday experiences for toddlers, incorporating the playfulness of the childhood imagination. She gathers inspiration for the books from observing her children and grandchildren.
The series features over 100 titles, in different formats including board books, picture books, concept books, interactive books, activity books, and pop-up books.
The Maisy series has sold over 28 million copies globally. The books have been published in 29 languages.
The School Library Journal named Maisy as a "staple in early childhood reading". Rustin noted that Maisy books utilise repetitions and similarities, which is beneficial to child readers as it aids familiarity and understanding. In their book Language development, Rachel Rudman and Felicity Titjen state Maisy books support children's language development and understanding of social relationships and concepts. Maisy has also been recognised for its positive and equal gender representation in children's media.
In 1999, a preschool animated children's television series based on the Maisy books was released. The show ran for one season and consisted of 26 episodes. In 2000, the show won the British Academy Children's Award for Pre-School Animation.
In 2024, a 2D animated television series titled My Friend Maisy entered development. The series is set to be co-produced by Trustbridge Entertainment and BBC Studios Kids & Family. Cecilia Persson, managing director of BBC Studios Kids & Family, stated the show will "embrace the legacy" of Cousin's Maisy books. My Friend Maisy is scheduled for release in 2026.