Learning how to write occluded genres is an elusive task (Swales, 1996) – even more so in the case of students writing in a second or additional language. To achieve discourse competence in the use of one of these genres, in this case the ‘statement of purpose’ typical of post-graduate programme admission forms, it is first necessary to fully understand its features at both the macrotextual and microlinguistic levels (Gillaerts, 2003; Bhatia, 2004). This qualitative study focuses on the writing of learners of Spanish as an additional language to analyse whether feedback provided by peers impacts the quality of the statements of purpose they write. Through a dual discourse analysis of their written work and in-class interactions during peer- feedback sessions, our study finds that, when properly trained and using tailored assessment tools, students can use peer-assessment profitably to improve the quality of their statements of purpose, as well as to acquire appropriate metalanguage to guide others. Our results thus reconfirm the beneficial effects of helping students to achieve feedback literacy.