Background <p>Adolescents in mental health care are gradually expected to assume greater responsibility for their health care. Patient portals may aid adolescents in this process by providing opportunities for treatment management and easier access to clinical information from their electronic health record (EHR). Research from other populations indicate a number of benefits from patient portal use. However, there is a knowledge gap concerning how adolescents in mental health care experience using patient portals. Therefore, the aim of the current study was to explore the experiences of using patient portals as adolescents receiving mental health care.</p> Methods <p>A qualitative study with individual semi-structured interviews with 17 persons who had experiences from using patient portals as adolescents in child and adolescent specialist mental health care in Norway. Data were analysed using Systematic Text Condensation.</p> Results <p>The results are presented in three themes: “A tool to assume responsibility”, “To be in control” and “A better understanding vs. negative reactions”. The informants talked about how they had used the patient portal to aid treatment management and that this had helped in their transition into adult care. The feature in the patient portal that the informants talked most about was the access to clinical notes written by healthcare providers.</p> Conclusion <p>The informants' experiences with using a patient portal in child and adolescent mental health care varied from managing treatment and getting a better understanding of their situation, to causing distress and challenging the trust in their healthcare providers.</p>