ObjectiveTo investigate individual effects of a three-week sleep robot intervention in adults with ADHD and insomnia, and to explore participants experiences with the intervention.MethodsA proof-of-concept study with a mixed-methods design (n = 6, female = 4) where a repeated ABA single-case study was combined with interviews. Data were collected with the Consensus Sleep Diary, wrist actigraphy, questionnaires on symptoms of insomnia, arousal, emotional distress, and ADHD, and through individual interviews.ResultsVisual analysis of the sleep diary and actigraphy variables did not support any effects from the robot intervention. Half of participants reported clinically relevant reductions on the Insomnia Severity Index from pre- to post-intervention. No changes regarding ADHD or arousal. Thematic analysis of the interviews resulted in three themes: (1) A pleasant companion, (2) Too much/not enough, and (3) A new routine.ConclusionAdjustments of the intervention ought to be made to match the needs of patients with both ADHD and insomnia before the next trial is conducted.