The present study examines the lexical patterning of altogether 4,022 instances of epistemic stance markers (EDs) across four levels of L2 proficiency (B1–C2) and three types of writing tasks (‘opinion’, ‘complaint’, and ‘letter’) by using the exploratory technique of Multiple Correspondence Analysis. The data stem from a Finnish learner English corpus, comprising of 1,773 texts. The results of the study showed that while the lexical patterns of EDs in the data seemed to be mostly related to task type, some proficiency-related patterns of ED use were observed across all tasks. In some cases, proficiency-related patterns could also only be observed in some of the tasks, suggesting task type and proficiency are, to some extent, interrelated when examining the use of EDs. The results thus suggest that both task- and proficiency-related constraints of EDs should be considered in both foreign language teaching and assessment.