Depersonalisation (DP) and derealisation (DR) experiences can cause clients and therapists a lot of confusion and anxiety. Therapist confusion has led to the under-recognition of DP and DR symptoms, under-confidence in working therapeutically with this client group and unequal client access to effective cognitive behavioural therapy (CBT) interventions. Client confusion has resulted in missed opportunities to engage in meaningful discussions with therapists about their DP and DR experiences and under-confidence that CBT can be of help. This article seeks to provide clarity for clinicians and clients around key misconceptions we have identified from the authors’ clinical experience of using CBT to treat DP/DR, both when presenting as symptoms in the context of other diagnoses and when presenting as a primary depersonalisation derealisation disorder (DDD). In addressing symptom misconceptions, we want to increase clinicians’ confidence when assessing DP and DR. We hope this will lead to productive discussions with clients and the inclusion of these symptoms in clinical formulations. We draw attention to client misconceptions in the hope that this facilitates better therapeutic dialogues about DP and DR and the potential benefit of CBT. Finally, we address therapist misconceptions about the use of CBT with this population in the hope that we can encourage more CBT therapists to work more proactively, confidently and effectively with DP and DR.