Attention deficit hyperactivity disorder (ADHD) is a condition with symptoms such as hyperactivity, impulsivity, lack of attention. ADHD can affect every day for an individual in a comprehensive way leading to poor performance and negative consequences. However, little is known about what influences treatment success and what patients experience as helping and hindering in this context. The aim of this current study is to evaluate helping and hindering factors for undergoing iCBT for ADHD. An additional focus on helping and hindering factors outside the treatment setting also included. Participants are recruited from a randomized controlled trial and those who completed the treatment is asked to participate in the study. The goal of the treatment is to increase everyday functioning and decrease ADHD symptoms. Participants are interviewed via telephone using a semi-structured interview guide and transcribed ad verbatim. The interviews are analyzed using thematic analysis. The results regarding helping and hindering factors are discussed in relation to treatment adherence and outcome of treatment. The study will inform how future treatments can be implemented in a better way.