Stakeholder theory has become an influential framework for addressing organizational challenges, including those related to sustainability. Yet, the inclusion of nonhuman stakeholders in stakeholder theory is complicated by ontological and epistemological obstacles. To overcome these, we turn to art and posthumanist practice theory and examine artist-led practices by focusing on the projects of two pioneering eco-artists, Helen Mayer Harrison and Newton Harrison. In this way we identify the ontological and epistemological challenges that impede the inclusion of nonhumans into stakeholder theory, (...) showing that artist-led practices allow for the inclusion of nonhuman stakeholders in two ways: (1) by specifying the temporal, spatial, and outcome distinctions that ontologically hinder their inclusion; and (2) by explicating the reframing of knowing and the emotional and imaginative dimensions of knowing that epistemologically enable their inclusion. We expand on the theorizing of nonhuman stakeholder inclusion by understanding the inclusion of nonhumans, first, not as a fixed state that is to be achieved but rather as one that materializes and gains meaning through specific practices of knowing; and, second, not as merely the absence of exclusion but rather as a dynamic interplay, where inclusion and exclusion mutually constitute one another. By advancing stakeholder theory’s theorizing and understandings of inclusion and exclusion, we also respond to urgent and contemporary environmental challenges. (shrink)