Optical coherence tomography (OCT) is a non-invasive optical imaging method that can generate high-resolution en-face and cross-sectional images of the skin in vivo to a maximum depth of 2mm. Whilst OCT holds considerable potential for non-invasive diagnosis and disease monitoring, it is poorly understood by many dermatologists. Here, we aim to equip the practicing dermatologist with an understanding of the principles of skin OCT and the potential clinical indications. We begin with an introduction to the technology and discuss the different modalities of OCT including angiographic (dynamic) OCT, which can image cutaneous blood vessels at high resolution. Next we review clinical applications. OCT has been most extensively investigated in the diagnosis of keratinocyte carcinomas, particularly basal cell carcinoma (BCC). To date, OCT has not proven sufficiently accurate for the robust diagnosis of malignant melanoma, however the evaluation of abnormal vasculature with angiographic OCT is an area of active investigation. OCT and in particular angiographic OCT also show promise in monitoring the response of inflammatory dermatoses, such as psoriasis and connective tissues disease to therapy. We additionally discuss a potential role for artificial intelligence in improving the accuracy of interpretation of OCT imaging data.