Siena Castellon is an 18-year-old multi-award winning neurodiversity advocate, bestselling award-winning author and a Young Leader for the Sustainable Development Goals endorsed by the United Nations. She is also the founder of Neurodiversity Celebration Week, an international initiative that challenges stereotypes and misconceptions about neurological differences by highlighting the strengths and accomplishments of the  neurodivergent community. In 2021, over 860,000 students and 1,400 schools took part worldwide, as well as more than 200 businesses, charities and government agencies.  

Siena is the author of The Spectrum Girl’s Survival Guide: How To Grow Up Awesome and Autistic, which won a 2021 Silver Nautilus Book Award. She is also the author of The Spectrum Girl’s Survival Toolkit: The Workbook for Autistic Girls.  

Most recently, Siena was awarded a £15,000 grant from the Paul Hamlyn Foundation to create an autism peer-to-peer mentoring programme that provides support services to autistic teenagers.   

Siena has won numerous international awards for her advocacy, including the 2021 Common Wealth Youth Award and the Campaigner of the Year at the European Diversity Awards. In 2020, Siena was a finalist for the International Children’s Peace Prize.