This article emerged through ethnographic research into strike action at a UK university. It provides three insights. First, it adds to the literature linking humour to resistance that has largely focused on subterranean, disguised, hidden, camouflaged or decaf opposition. The resistant humour explored in this case is more diverse and challenges extant distinctions because it was overt and covert, individual and collective, decaf and ‘real’. Second, it posits that during strike action the already ambiguous distinction between humour and seriousness becomes even more blurred. Third, it contributes to our understanding of power-resistance relations through introducing the term solidaristic humour which conveys a neglected expression of opposition that reflects and seeks to galvanize solidarity.