In Hong Kong schools, source-based writing has risen in prominence in recent years with the incorporation of inquiry project-based learning (PjBL) into the curricula. Understanding how school students write from sources in this context will constitute a crucial step toward identifying potential problems and targeting educational strategies. In this paper we report an exploratory study of how junior secondary school (Forms 1–3) students reported sources in their research-based group project reports in the Liberal Studies subject in the environment of a Wiki online platform. Our analyses of a sample of 30 project reports focused on discovering how the students used reporting verbs and expressions to report information from sources, and how they expressed positive and critical evaluation of their sources. Our study addressed a gap in the literature by examining school students’ source-use practices in their first language, with valuable pedagogical insights generated and avenues of future research suggested.