The purpose of this paper is to explore what thinking with a philosophy of "becoming" might produce in terms of conceptualising "Learning for Sustainability" ("LfS"), a recent development in Scottish educational policy. The paper posits that animism and the immanent materiality of a philosophy of becoming have important ramifications for contemporary approaches to sustainability education. "Becoming" is described and its relationship to prevailing "systemic" approaches to sustainability education explained. "LfS" is then described and conceptualised with a philosophy of becoming by examining its implications for Education for Global Citizenship and Outdoor Learning. The concepts of communication as expression; the subject undone (as haecceity); the distinction of "nature" as "other"; and the centrality of a storied world are discussed as important elements of "LfS" becoming. Lastly, teaching materials and interviews with two initial teacher educators help create a rhizomatic assemblage of teacher education practice and "LfS" as becoming. This assemblage creates lines of flight for considering practice, including making explicit the expressivity of communication in course descriptor/teaching/learning relationships; highlighting the place/becoming assemblages of "indoor" and "outdoor" learning environments; and storying the world with learners through haecceity description/experimentation.