Labour markets in most European countries continue to be characterized by substantial earnings differences between men and women, yet policies aimed at reducing these inequalities often lack popular support. We suggest that people’s beliefs about the size and the source of these inequalities might be crucial to explain why individuals support or oppose gender equality policies. Scholars emphasizing the importance of inequality aversion and gendered labour market segregation suggest that people likely underestimate the size of the gender pay gap and would increase support for gender equality policies if adequately informed. Another branch in the literature, however, suggests that this expectation may be misguided as people do not dislike inequality per se but only inequality they deem unjustified. Thus, informing individuals about the overall gender wage gap might be insufficient to shift their policy preferences, as many may attribute these pay differences to women's choices rather than to systematic disadvantages in the labour market. This study empirically tests these two theoretical arguments using a preregistered cross-national information provision experiment. The experiment, currently fielded in Germany and planned for the US and Sweden in January 2025, informs participants about gender inequality in pay within their country, varying both the size (low vs. high) and the type (unadjusted vs. within-job adjusted) of gender pay information presented. Using this data, we examine whether different types of gender pay gap information can increase support for gender equality policies and investigate whether factors such as issue salience, misinformation, or justice beliefs drive these effects.