The role of laughter in evaluating language use has received little attention in language attitude research and laughter studies. In this paper, we analyse how Nigerian students use laughter to perform social actions in evaluating language use in Nigeria. The study is informed by a discursive psychology, social identity and politeness analytical framework and draws on transcripts of 18 focus group discussions involving 132 students from three Nigerian universities. The analysis shows that participants use laughter to deride the outgroup, reinforce ingroup coherence, and mitigate self-face-threatening linguistic behaviour. In contrast to common views in the literature that laughter is used to show superiority, we found that laughter can also be a marker of inferiority, especially when people discuss their own marked linguistic behaviour. The study demonstrates that ingroup-outgroup categorisation impacts the extent to which individuals are polite and impolite in their use of laughter when evaluating language use. We argue that a comprehensive theory of laughter should include the functions of laughter not only as a response to humourous stimuli but also as a device people use to ‘do things’ in discourse, such as negotiating shared cultural knowledge and identity. In showing how participants use laughter to evaluate language in interaction, our study extends research on language attitude and stereotypes in text and talk.