Inclusion Criteria:  Age 12 to 17 years, confirmed by the caregiver and subsequently by the patient record system Take Care. A diagnosis of BDD, based on the 5th edition of the Diagnostic and Statistical Manual of Mental Disorders (DSM-5), confirmed by the assessor at the pre-treatment assessment. A total BDD severity score on the BDD-YBOCS-A ≥24. confirmed by the clinician-reported BDD-YBOCS-A performed at the pre-treatment assessment. A minimum of one available caregiver (parent) to support the child/adolescent throughout the treatment. Confirmed by the caregiver at the telephone screening or/and pre-treatment assessment. Regular access to a desktop or laptop computer connected to the Internet, with the ability to receive e-mails, as well as a mobile phone to receive SMS (one of each per family is enough). Confirmed by the caregiver at the telephone screening or/and pre-treatment assessment.  Exclusion Criteria:  Previous CBT for BDD for a minimum of eight sessions with a qualified therapist within the 12 months prior to assessment. Confirmed by the caregiver at the telephone screening and/or pre-treatment assessment. Simultaneous psychological treatment for BDD, confirmed by the caregiver at the telephone screening and/or pre-treatment assessment. Initiation, adjustment or change of any selective serotonin reuptake inhibitors (SSRI) within the six weeks prior to the pre-treatment assessment. Confirmed by the caregiver at the telephone screening and/or pre-treatment assessment. A diagnosis of organic brain disorder, intellectual disability or a psychiatric disorder (such as psychosis, bipolar disorder or eating disorder) that could interfere with the completion of the treatment. Confirmed by the caregiver at the telephone screening and/or pre-treatment assessment, with help of information from the caregiver and the child/adolescent, and the MINI-KID interview. Immediate risk to self or others requiring urgent medical attention, such as current risk of suicide or self-injurious behaviours. Confirmed by the assessor at the telephone screening and/or face-to-face or video conference pre-treatment assessment, with help of information from the caregiver and the child/adolescent, and the suicide questions on the MINI-KID interview. Child and caregiver not able to read and communicate in Swedish. Confirmed by the caregiver or assessor at the telephone screening and/or pre-treatment assessment.