This paper investigates authentic writing through the use of wikis by Year 7 ESL learners in a secondary school in Hong Kong. The wikis were used as a collaborative writing platform to produce – with minimal input and support from their teachers – wiki content that describes the different facilities and features of their school. Over a period of two months, as an integral part of their ESL homework, groups of students designed and put together, through a series of successive drafts, a description of their secondary school which they had joined from primary school a few months previously. After an initial overview of how wikis function in terms of editing and revision, the paper describes the process one group of learners went through. Samples are provided of the students’ intermediate and final drafts, as well as snapshots of the amount and the types of writing produced at each stage. The students’ final draft became a printed brochure of their ‘new’ school to be distributed to parents. In the light of this real ‘outcome’, the paper discusses the place of authentic writing, situated within the domains of creativity and task-based learning, in a school’s ESL programme.