The present article concentrates on the advent of gender mainstreaming as a method of incorporating gender perspective into public policies. It analyses the historical as well as the epistemological foundations of gender mainstreaming laid down during the Beijing Platform for Action Conference of 1995. Furthermore, it analyses the factors that led to the adoption of gender mainstreaming by the European Community’s institutions and the policy context in which it has been applied ever since. The aim of this article is to portray the epistemological framework of this soft law method as an open signifier for different perceptions of gender. For these purposes, the article analyses the “subject positioning” within the framework of 13 projects on tackling human trafficking in EIGE’s tool for good practice sharing .