The question of the role of non-humans in conservation has given rise to a number of pressing debates. Proponents of ecocentrism, multispecies ethnography or the post-human turn have all aimed to promote more-than-human perspectives and attribute equal importance to all forms of (animate) life. However, their relative failure to translate this advocacy into actual conservation decision making has given rise to the question how to appropriately represent non-humans in conservation governance for more inclusive and just conservation. This paper introduces and outlines an approach to addressing this issue we term multispecies constitutionality by exploring a case of human-bear interactions in the commons of the Rodopi mountains of Bulgaria, where outmigration and postsocialist transformations have emptied space for brown bears in areas previously inhabited or managed by humans. Building on longstanding exploration of common pool resource governance, growing discussion of “constitutionality” is intended to capture how the “agency and creativity” of bottom-up governance processes are able to effectively manage natural resources in the absence of external authority, while still accounting for local power relations in a way commons research has often overlooked. Yet both commons and consitutionality research has thus far remained focused on how humans decide among themselves how to interact with nonhumans without actively including the latter. Here, we expand our focus to take into account calls for inclusion of “more-than-human” perspectives in governance and decision-making to achieve a more holistic understanding of human-bear coexistence and introduce an approach for investigating multispecies interactions that accounts for the role of non-human actors in shaping shared landscapes.