Ruth Paul is a Wellington-raised writer and illustrator. She completed a Bachelor of Arts at Victoria University of Wellington, and a Diploma of Visual Communication Design at Wellington Polytechnic (now Massey University Wellington).

In 1991, she became a freelance illustrator. As an illustrator only, Paul’s works include Tom’s Story (Mallinson Rendel Publishers, 1997) by Mandy Hager, Penguin’s Day Out (Mallinson Rendel Publishers, 1999) by Vivienne Joseph, and the Mini Whinny series by Stacy Gregg (Scholastic NZ, 2018).

In 2002 she began to write her own books, with her first publication as an author/illustrator being The Animal Undie Ball (Scholastic, 2004). She has since written and illustrated more than 18 books, including The King’s Bubbles (Scholastic, 2007), Two Little Pirates (Scholastic, 2010), Stomp! (Scholastic, 2011), Hedgehog's Magic Tricks (Walker Books 2012), Bad Dog Flash (Scholastic 2013), I Am Jellyfish (Penguin Randomhouse 2018) and the Little Hector series (Penguin RandomHouse 2018).

Her books have been translated into different media forms. The Animal Undie Ball was produced by Capital E as a stage performance with the Java Dance Company in their 2007 Children’s Arts Festival. The Animal Undie Ball, Superpotamus and Two Little Pirates have all featured on Wurrawhy, Channel 10 Australia's preschool television series, and Stomp! has appeared on the ABC network's children's show Playschool. Bad Dog Flash has also been published as an ebook via its US publisher (Sourcebooks, 2014).

Her poem 'Sparkle' is included in A Treasury of NZ Poems, edited by Paula Green (Random House NZ, 2014), and a number of her stories have been read on Radio New Zealand's Storytime programme. Her books have been translated into Māori, Korean, Chinese, French and Spanish and published in New Zealand, Australia, the United Kingdom, Canada, the United States, China and Korea.

The King’s Bubbles won the Children's Choice Award at the 2008 New Zealand Post Book Awards for Children and Young Adults. Stomp! was also a finalist in the Best Picture Book category of the 2012 New Zealand Post Book Awards for Children and Young Adults, and I Am Jellyfish won Picture Book of the Year in the same awards in 2018, with Mini Whinny Happy Birthday to Me shortlisted for 2019. The King's Bubbles won the 2008 PANZ Book Design Award in the children's category, and I Am Jellyfish was shortlisted for the same awards in 2019. Bad Dog Flash was selected for the Kids Indie Next List (Autumn, 2014) by the American Booksellers Association after is publication in the United States. Many of her books have been included in the Storylines Notable Books list.