The 1997 Treaty of Amsterdam places equality between women and men among the explicit tasks of the European Union and obliges the EU to promote gender equality in all its tasks and activities. In the strategy of Gender Mainstreaming it is recognised that gender should be an essential part of policies on science, labour market and employment, development co-operation and education. The Gender Mainstreaming approach that has been legitimated by this Treaty is backed by legislation and by positive action in favour of women (or the "under-represented sex"). With regard to gender inequality, the EU has both a formal EU problem definition at the present time, and a formalised set of EU strategies.

The world-wide adoption of the Gender Mainstreaming strategy can be traced back to the UN-conference in Beijing, and is connected to earlier agreements, such as CEDAW. Since Beijing, the EU has been among the major pioneers in developing Gender Mainstreaming, both by starting a process of Gender Mainstreaming within the European Commission itself, by diffusing information to Member States and candidate states in a number of conferences and seminars (in Brussels, Bled, London), and through the reorganisation of EU-policies so that Member States can hardly escape engaging in Gender Mainstreaming too (as in the case of the new regulations for the Structural Funds). After Beijing, several national governments have also announced that Gender Mainstreaming will be adopted as part of their continuous efforts to achieve gender equality. Countries such as Sweden, Norway and the Netherlands took the lead in developing specific tools. At yet another level, supranational organisations such as the Nordic Council of Ministers, the Council of Europe, the World Bank and the ILO started initiatives directed at their respective constituencies. At most levels, feminist movements exert pressure in favour of Gender Mainstreaming.