Efforts to establish, test and analyse hypotheses regarding cross-country variations in women's economic status are hampered by the lack of a readily accessible and easily used information resource on the various dimensions of gender inequality. Addressing this gap, this paper introduces the Gender, Institutions and Development data base (GID) www.oecd.org/dev/institutions/GIDdatabase of the OECD Development Centre. The GID constitutes an important improvement upon existing sources, notably because it incorporates institutional variables related to norms, laws, codes of conduct, customs, and family traditions that heretofore have been neglected in quantitative comparative studies. To illustrate the utility of the GID, the paper models the determinants of women's participation in the labour force -- an indicator of gender equality as well as an important ingredient for long-run economic growth -- and demonstrates that the economic role of women hinges critically on variations in discriminatory social institutions. (A bibliography is included. Contains 4 footnotes, 6 figures and 6 tables.)