This chapter investigates the extent to which native and non-native writers make use of collocations in their written texts. It provides a detailed comparative analysis of the verb-noun and adjective-noun collocations produced in the 324,304-word Louvain Corpus of Native English Essays (LOCNESS) and the 248,513-word Nigerian Learner Corpus of English (NILECORP-C1). The findings indicate learners in a context where they have frequent exposure to the input outside the classroom can produce as many collocations as native speakers do. However, the nature of the collocations produced by the native speakers, in terms of their structural and semantic properties, is noticeably different from the ones produced by the learners. The difference in the collocations in the written texts produced by native speakers and L2 learners does not necessarily lie in the quantity of the collocations produced but in the linguistic complexity of the collocation in terms of the structure of their constituents and how collocations are used to express various shades of meanings. The findings also indicate the learners’ knowledge of incongruent collocations lags behind their knowledge of congruent collocations. The discussion of the findings highlights the influence of first language background on the production of L2 collocations.