Education for Sustainability is an internationally recognised field of learning that is currently mandated as a cross-curriculum priority in the Australian curriculum. Empirical research into children’s views about sustainability, and how they develop sustainability knowledge, however, remains limited. This article focuses on research that investigated children’s perspectives of sustainability in Victoria, Australia. The children were recruited through the Sustainable School Expo where they delivered keynote presentations about their school’s respective Education for Sustainability initiatives. Data were generated from interviews with 16 children aged from 9 to 13 years and included a set of self-created and designed sustainability artefacts. The article contends that children have strongly conceptualised ideas about sustainability that are developed through interactions with material entities (human/more than human) in diverse environments. A key finding suggests that children become vital stakeholders in Education for Sustainability through experiential, investigative, sensorial and place-oriented ways of learning, which informs how they build sustainability knowledge.