Joanna Nadin is an English author of children's and teen fiction best known for the Rachel Riley series of novels Based on Nadin's own childhood, the series follows the comedic narration of a 13-year-old girl growing up in Saffron Walden, Essex.

She is a winner of the Lancashire Fantastic Book award, Blue Peter 'Book of the Month' and Radio 4 Open Book 'Book of the Year', has twice been shortlisted for the Queen of Teen award, and Spies, Dad, Big Lauren and Me was selected for the Richard and Judy Book Club. In 2011, Penny Dreadful is a Magnet for Disaster was shortlisted for the Roald Dahl Funny prize.

Nadin previously worked as a policy writer for the Labour Party (UK). In 2001, she became a special adviser to Tony Blair. She continues to freelance as a speechwriter and editor.

In 2016 a primary-aged reader wrote to Nadin, pointing out a grammatical mistake in her book "The Stepmonster". Nadin's humorous letter in reply went viral.