Unwillingness of certain individuals to accept the reality of anthropogenic climate change threatens mitigation and adaptation efforts. Gender (being male), political conservatism and system-justifying ideologies are potent unique predictors of anthropogenic climate change scepticism but have typically been examined in isolation. We tested additive, interactive and mediation models of gender, political conservatism, social dominance orientation (SDO) and general system justification (GSJ) in predicting scepticism with a representative New Zealand sample (N = 8199; 74.7% New Zealand European, 55.1% female). Climate scepticism is greater for men and those who endorse system-justifying ideologies. Notably, the anti-egalitarianism dimension of SDO mediated the gender–scepticism link and the association between scepticism and this SDO dimension was stronger for higher levels of political conservatism and GSJ. Exploratory moderated mediation analyses indicated an increase in the indirect influence of being male on scepticism via SDO at increasing levels of GSJ and political conservatism.