This study explores the effect of teaching collocations on building academic vocabulary and hence improving academic writing abilities. A pre-/post-test experimental design was used to analyse collocations produced in two tasks completed by the study’s participants, English majors at a university in Burundi. They were presented with a completion task and an essay-writing task before and after being exposed to a collocation-based syllabus. The syllabus was designed by selecting target words from the Academic Word List (AWL) (Coxhead 2000) and collocations from the Oxford Collocations Dictionary for Students of English (Crowther, Dignen, and Lea 2002). The awareness-raising approach (cf. Barfield 2009) and an adapted version of McCarthy and O’Dell’s (2005) collocation web model were the techniques adopted for teaching collocations. The results show that participants performed significantly better on the post-test than on the pre-test in their production of collocations in both tasks. This suggests that an intervention contributes towards building students’ productive use of collocations in both cued recall and essay writing, supporting earlier findings (cf. Barfield 2009, Seesink 2007). In light of these findings, pedagogical consequences and avenues for improving higher education students’ use of collocations in writing are discussed.