Using games as part of the intervention and support process (sometimes referred to as 'gaming therapy') is an increasingly popular method of supporting autistic youth to develop social competencies and other skills because they are believed to be inherently motivating and fun for youth. Some emerging research has indicated that intervention programmes using games can be beneficial for autistic youth, but little is currently known about why, how and for whom they work. This study conducted a realist evaluation of a programme using the video game "Minecraft" for autistic youth, comprising interviews and observations with autistic youth (