Ecological dominance is a central concept in the study of interspecies and species- environment relations. Yet, although theoretical and empirical work on ecological dominance has progressed in many scientific disciplines, the psychology of ecological dominance remains understudied. The present research attempts to advance theoretical and empirical inquiry on ecological dominance as a psychological predisposition, examining how and why it influences humans’ perceptions, attitudes, and behaviors across different relational domains (i.e., intraspecies, interspecies, human-environment). To this end, we validate a novel measure, the Ecological Dominance Orientation (EDO) scale, based on the popular iconic depiction of eco-centric vs. anthropocentric arrangements of the relationship between humans, non-human animals, and the natural environment. In two pre-registered studies conducted across 2 countries (N = 1,312), we demonstrate that EDO a) shapes attitudes in a similar fashion both within and between different relational domains (i.e., intergroup, interspecies, human-environment relations), b) is uniquely predictive of numerous socially consequential attitudes across relational domains (i.e., modern sexism, modern racism, speciesism, anthropocentrism) over and above established measures of personal ideology and beliefs, and c) is reliable over time. This research extends classical Social Dominance Theory (Sidanius and Pratto, 1999) by theorizing about the socio-ecological roots of intergroup, interspecies, and human-environment relations as hierarchically structured power relations. Theoretical and practical implications of social and ecological dominance orientations are discussed.