Contemporary views of literacy as a wide range of sociocultural practices acknowledge a comprehensive account of adolescents' literate lives, which includes previously unrecognised vernacular literacies. Contrasting descriptors such as official/unofficial and sanctioned/unsanctioned have been used to describe adolescent writing from different domains. While these distinctions are useful, the boundaries between them are subject to transgression. This paper draws on ethnographic data collected in a vocational education training programme for Year 10 students identified as being at educational risk. Adopting a communities of practice perspective, the study focuses on the school-sponsored writing practices of a group of Aboriginal English speaking girls. It describes how the girls recruited resources from communities of practice in which they participated outside the classroom. The findings indicate three ways in which the boundaries between school-sanctioned and vernacular literacy practices became disrupted, including: (1) the authorisation of unofficial practices; (2) the authorised and unauthorised infusion of unofficial content; and (3) the recruitment and acceptance of teen writing styles in school-sponsored tasks. It is argued that challenging the boundaries between official and vernacular literacies may be not only inevitable, but worthy of encouragement as a strategic way of promoting the participation of disaffected students in school-sponsored literacy activities.