The article discusses epistemic stance in spoken L2 production. Using a subset of the Trinity Lancaster Corpus of spoken L2 production, we analysed the speech of 132 advanced L2 speakers from different L1 and cultural backgrounds taking part in four speaking tasks: one largely monologic presentation task and three interactive tasks. The study focused on three types of epistemic forms: adverbial, adjectival, and verbal expressions. The results showed a systematic variation in L2 speakers' stance-taking choices across the four tasks. The largest difference was found between the monologic and the dialogic tasks, but differences were also found in the distribution of epistemic markers in the three interactive tasks. The variation was explained in terms of the interactional demands of individual tasks. The study also found evidence of considerable inter-speaker variation, indicating the existence of individual speaker style in the use of epistemic markers. By focusing on social use of language, this article seeks to contribute to our understanding of communicative competence of advanced L2 speakers. This research is of relevance to teachers, material developers, as well as language testers interested in second language pragmatic ability.