Recent research highlights the importance of considering how values, ideologies and worldviews inform attitudes on the environment and climate change. Although social dominance orientation (SDO) and right-wing authoritarianism (RWA) have been linked to environmentalism, the nature and extent of these relationships is unclear. We meta-analyse correlations between SDO, RWA and six indices of environmentalism from 53 independent samples identified from database searches and contact with researchers in the field. We show that SDO and RWA have comparable associations with environmentalism, regardless of how this is measured. We re-analyse data from 16 independent samples using regression to assess the unique relationships, finding that both ideologies independently predict environmentalism. For SDO, we show that the effect size depends on the sample type, with a weaker association in student samples than in the general population. These results highlight the role of ideological attitudes as a barrier to belief and action on environmental issues.