Anxiety Disorders are the most common mental health problem across the lifespan, create a huge personal burden for individuals and substantial economic burden for society. They have a particularly early age of onset and often run a chronic course- with half of all people who experience an anxiety disorder first experiencing those difficulties by the age of 11 years. Yet we have recently found that less than 3% of children with an anxiety disorder receive CBT, despite this being the only psychological treatment that has an evidence base. This talk will describe observational and experimental research on the development and maintenance of child anxiety disorders, how that has underpinned a brief psychological intervention for child anxiety disorders, and findings from randomised controlled trials to evaluate the approach. I will also give an overview of upcoming research to further increase access to treatment for children with anxiety disorders, including an NIHR programme grant that is about to start in Oxford.