The goal of this clinical trial is to evaluate the preliminary outcomes of concentrated exposure and response prevention for children with obsessive-compulsive disorder (OCD) in regular clinical practice. It is a non-randomised open label evaluation where children 6-12 years with OCD who are patients at the Child and Adolescent Psychiatry (CAP) at Uppsala University Hospital will be rectruited together with their legal guardians. The treatment will be delivered by trained therapists in regular outpatient care. The main question the study aims to answer is: What are the preliminary treatment effects of concentrated exposure and response prevention with regards to OCD-symptoms, functional impact, family accomodation and clinician ratings of severity and improvement? Participants will receive psychoeducation (in group format) and exposure and response prevention (9-12h concentrated to one week, individual format). Outcomes will be measured on structured interviews, clinician ratings, and validated questionnaires pre-treatment, post-treatment and at a six month follow-up.