The notion of persuasion in the public sphere is a recurrent topic in pragmatic studies, which necessarily draw on findings from social and cognitive psychology. The paper addresses the vexing issue of the interdependence between humour and persuasion, with special attention being paid to advertising discourse and court discourse. A paradoxical situation can be observed regarding the prevalence of humorous advertisements and contradictory data about the effectiveness of humour as a persuasive device. Empirical studies have failed to obtain conclusive results about the persuasive power of humour. A specific shift of perspective in research approach is here advanced in order to unravel the intricacies of the matter. Moreover, referring to rhetorical and socio-psychological postulates, the paper aims to explain a few mechanisms underlying humour deployed as a persuasive weapon at court. The hypotheses put forward here are based on scholarly literature on persuasion and real-life language material, which sheds light on practitioners’ persuasive practices.