Gender inequality is an important and visible issue for OECD countries and the costs are borne at both social and economic levels. This paper draws on the experiences of OECD countries and aims to provide insights into how the budget process can develop as a tool to support gender equality goals; the different ways in which gender budgeting can be implemented; and the factors that help provide an enabling environment for gender budgeting. Arising from this analysis, this paper proposes initial guidelines for designing and implementing gender budgeting to assist countries in putting in place an effective and sustainable approach. It also presents a first pass at a composite index for gender budgeting which assesses the extent to which OECD countries' gender budgeting efforts are characterised by a strong strategic framework, effective tools of implementation and an enabling environment.