The movement from STEM to STEAM, with its emphasis on real-world applications, promises to meet the changing needs of a globally connected world. However, the potential of transdisciplinarity to inspire and deepen our understanding of who we are and how we make sense of a world in turmoil remains undertheorized. This article makes a case for repositioning STEAM education as democratized enactments of transdisciplinary education, where arts and sciences are not separate or even separable endeavors. Drawing upon posthumanist theorizing, three projects will exemplify transdisciplinarity across music, mathematics, and science education. Transgressing and transcending disciplinary boundaries, and attending to both human and nonhuman perspectives, we invite a rethink of the work of schools, going beyond democratizing creativity to fully enact posthumanist transdisciplinarity.