Résumé : We tested the internal reliability and predictive validity of a new 4-item Short Social Dominance Orientation scale (SSDO) among adults in 20 countries, using 15 languages (N = 2130). Low scores indicate preferring group inclusion and equality to dominance. As expected, cross-nationally, the lower people were on SSDO, the more they endorsed more women in leadership positions, protecting minorities, and aid to the poor. Multi-level moderation models showed that each effect was stronger in nations where a relevant kind of group power differentiation was more salient. Distributions of SSDO were positively skewed, despite use of an extended response scale; results show rejecting group hierarchy is normative. The short scale is effective. Challenges regarding translations, use of short scales, and intersections between individual and collective levels in social dominance theory are discussed.