The purpose of this article is to analyse the phenomenon of humour in therapy. Rod Martin [1] defines humour as a fundamentally positive emotion referred to as amusement, triggered by cognitive processes of appreciation of perceived amusing stimuli and non-threatening, funny incongruence, accompanied by specific facial and vocal expressions of laughter. Humour in therapy can play a significant role. It might be a form of therapy, one of the therapist’s competences, as well as a therapy technique. Notwithstanding the multiple qualities of humour, we need to recognise the risks involved in utilising it in the therapeutic process. In fact, the lack of ambiguity in the humorous message is likely to lead to misunderstandings between the patient and therapist. The patient may not have a clear comprehension of the humorous message and may not perceive the message to be humorous. They may also consider the humorous message inappropriate. Furthermore, humour is not a homogeneous phenomenon. There are styles of humour that are adaptive in nature, such as: affiliative humour and self-enhancing humour, and styles of humour that are non-adaptive, such as aggressive humour and self-defeating humour. The variability of humour styles in therapists and patients also needs to be addressed, as not all styles are suitable for therapy – they can disrupt relationships or impair patients’ self-esteem.