Many trials answer the question "What works"? and often miss the question "why does it work/not work"? Realist evaluation answers the question "What works for whom under what respects and circumstances". That is, it aims to answer the question "what works" as well as why it works and in what contexts it works in.There have been lots of technologies made for children and young people with Attention Deficit Hyperactivity Disorder (ADHD) to help them self-manage their ADHD (Powell et. al, 2017). However, when research is conducted around these technologies, the context they are delivered in is often ignored and therefore answers the question "what works" without testing why. Context is important as it can be divided into two: 1) environmental (where the intervention is delivered) and personal (things that change between individuals e.g. some people with ADHD have other needs associated with other conditions for example dyslexia and autism). Therefore this project is using a realist evaluation methodology to find out what works and why for these technologies. It will also highlight adaptations that are required for this complex population.