Parents report that almost 70% of children with autism spectrum disorders (ASD) are picky eaters. However, picky eating is often overlooked as clinicians focus on treating core symptoms of ASD. Picky eating causes family conflict, restricts family activities, increases parent stress, and puts children at risk for health problems. There are established treatments for picky eating in young children with typical development and ASD, but little is known about effective treatment in older, cognitively higher-functioning children with ASD. The overarching goal of this project is to develop a new group-based treatment to decrease picky eating, designed specifically for children with ASD. This project will involve individuals with ASD, parents, nutritionists, and therapists in the development of the treatment so it will be most useful for those receiving or administering the intervention. The BUFFET (Building Up Food Flexibility and Exposure Treatment) program addresses the glaring need for a treatment that will focus on the complex reasons for picky eating in ASD. This intervention will include four primary treatment modules: 1) Anxiety management and exposure to foods that produce anxiety, 2) Scripts for being flexible with food, 3) Sensory education about foods, and 4) Taste identification training. Treatment activities include: changing negative or fearful thoughts about food into positive and flexible thoughts, providing praise and reinforcement when children are flexible with foods (while ignoring food refusal), developing reward systems to praise food flexibility, parent training for using BUFFET strategies at home, visual supports and scripts/routines, and increasing food intake by eating in social groups. This project will produce a treatment manual with treatment exercises. In addition, the project will collect data about whether the BUFFET program works in a clinic setting, as well as whether children, families, and therapists like the treatment and feel that it meets their expectations. In sum, this project establishes a new, creative treatment program for the underappreciated issue of picky eating in children with ASD, with the immediate goal of improving the quality of life of children with ASD and their families.