Aim: The study aim was to explore adolescents' with co-existing ADHD and medical disorder (MD) perceptions of everyday life and support from parents and healthcare professionals. Design and methods: In this qualitative study, 10 adolescents aged 13–17 years diagnosed with ADHD and a MD were included from a general pediatric hospital clinic and a child and adolescent psychiatric hospital clinic. Data obtained through semi-structured interviews were analyzed using thematic analysis. Results: The adolescents' perceptions were categorized into four themes: 1) ADHD perceived as part of the adolescent's self-understanding – yet with daily frustrations, 2) MD perceived as an interruption in everyday life, 3) ADHD and MD – an overlooked dual task, and 4) the need for supportive relationships in navigating ADHD and MD. Conclusion: Living with co-existing ADHD and MD is a complex dual task, as ADHD and MD interfere with each other in everyday life. However, the adolescents overlook the dual task as they believe their difficulties would be resolved if the MD was eliminated. Moreover, supportive relationships are essential in navigating the complexities in living with co-existing ADHD and MD. Nevertheless, the adolescents take a passive role in the encounters with the healthcare professionals, whereas they are more active in encounters with peers, parents and teachers. Practice implications: Healthcare professionals treating and caring for adolescents with co-existing ADHD and MD need interventions facilitating patient involvement in a patient-centered approach to support both adolescents and healthcare professionals in recognizing the dual task of having co-existing ADHD and MD.