In recent decades, humans’ love and abuse of other species have both increased exponentially. People often express both a concern about the well-being of animals, and support for using animals in research and for consumption. What attitudes enable humans to support these structures and practices of widespread abuse, suffering, and extinction? How is it possible to hold profoundly conflicting views, valuing and loving a select few animals, while contributing to abhorrent treatment of countless others? In answering these questions, we will draw from psychology to outline the study of intergroup relations among human groups, extending the conceptual frameworks across species. Human attitudes toward other species mirror many of the social and cognitive structures in prejudice toward human groups and stem from similar ideologies about social hierarchy and inequality. Because of these similarities, extensive research pertaining to prejudice reduction strategies for inter-human group conflict may also be promising in addressing human relationships with other animals. Further, research has demonstrated that challenging one form of prejudice can reduce prejudice overall, benefiting human and non-human groups and potentially contributing concurrently to social and environmental justice, and to One Health initiatives.