Far from being a monolithic approach to psychotherapy, cognitive behavioural therapy (CBT) is in fact an umbrella term to describe a family of psychological therapies that share many common features but also have nuanced differences. Of the CBTs, two are often conflated under the ‘CBT’ moniker, namely cognitive therapy (CT) and rational emotive behaviour therapy (REBT). In this article, we explore some of the key differences and similarities between CT and REBT, touching on philosophy, practical implementation, and literature. We provide a brief hypothetical case study to demonstrate the different ways a therapist using CT and REBT might tackle the same client problem. We do not declare either approach superior, but suggest each might have their advantages in certain contexts and acknowledge that skilful practitioners could, and often do, integrate both approaches. As CBT continues to evolve and move into new areas, it is important that psychology practitioners and researchers are clear about which specific approach to CBT they are delivering, measuring and/or reporting on.