As products of the Anthropocene, the epoch of human ecological impact, models of environmental and social sustainability have been rooted in humanism, centering human agency and taking humanity as the prime reference point in understanding the world. Discourses around sustainability pose questions of how we are trying to sustain our world and our central place in it. With these questions in mind, we examine the role of science education for sustainability and as a tool for enacting societal change and interacting with the world responsibly. Science education is particularly concerned with helping learners cultivate tools and develop scientific literacy for understanding and interacting with the world. This is key to the ability of current and future generations to meet the challenge of building and maintaining a sustainable world. Yet, these tools are rooted in anthropocentric and Western ways of understanding our relationships with and in the world, which maintains myths such as the neutrality of digital technology or linear forms of progress. We turn to posthuman perspectives to consider an alternative onto-epistemological stance that decenters human agency and foregrounds the co-constitutive and intra-active nature of the world. We argue that scientific literacy and science education for sustainability can act as channels for our species to move beyond ecological sustainability to an understanding of humanity’s entanglement with the world. Life in all its forms, from micro to macro is about relationships with cultural and natural ecologies. Any changes in these relationships can lead to the sustaining, altering, or threatening of these ecologies. In light of this recognition, we explore the implications of posthumanist thought for science education and literacy as learners seek a more sustainable world and a more harmonious place for humanity within it.