Professional boundaries are an important aspect of social work theory and praxis – yet it is an underexplored topic within the research literature. Research often explores specific types of professional boundary issue rather than exploring social workers’ boundary stories or boundary narratives. In contrast, this qualitative study explored UK social workers’ broader understanding and experience of professional boundaries. This paper will examine one of the research themes – Humour as a boundary breaker. By using humour, social workers were able to (...) break down the boundaries that often impede effective practice. Participants also used humour to build connections with service users, colleagues and other professionals. Nonetheless, there were various aspects of this practice that raised serious issues related to power, prejudice and discrimination. This theme is important to explore because of how relevant it was for participants’ practice and because humour is also an underexplored topic within the social work literature. (shrink)