This Element provides a systematic overview and synthesis of corpus-based research into collocations focusing on the learning and use of collocations by second language (L2) users. Underlining the importance of collocation as a key notion within the field of corpus linguistics, the text offers a state-of-the-art account of the main findings related to the applications of corpora and corpus-based measures for defining, identifying and analysing collocations as related to second language acquisition. Emphasising the quality of L2 collocation research, the Element illustrates key methodological issues to be considered when conducting this type of corpus analysis. It also discusses examples of pertinent research questions and points to representative studies treated as models of good practice. Aiming at researchers both new and experienced, the Element also points to avenues for future work and shows the relevance of corpus-based analysis for improving the process of learning and teaching of L2 collocations.