Whereas social scientists have devised various ways to measure representation gaps between the political elite and the masses across nations and time, few datasets can be used to measure this gap for particular social groups. Minding the gap between what parties social groups vote for and what parties actually attain seats in parliament can reveal the position of social groups in the political power structure. We help to fill this gap with a new publicly available dataset, Party Representation of Social Groups (PaReSoGo), consisting of 25 countries and 150 country-years, and a method for its construction. We used the European Social Survey 2002–2016 and ParlGov data for this time span to create a Dissimilarity Index. To demonstrate the utility and flexibility in the combination of cross-national surveys and administrative data, we chose social groups of gender, age, and education, as well as intersectional groups based on gender and age, and attitudinal groups. We conclude this research note with empirical illustrations of PaReSoGo’s use.