This report seeks review trends in and causes of the gender pay gap in Portugal over the past two decades. To this end, the authors have used the ILO’s factor-weighted gender pay gap - a method for generating estimates of the gender pay gap that removes some of the major composition effects caused by the existence of clusters - and the measurement methodology by Fortin et al. (2011). The report also examines the national legal and policy frameworks to promote gender equality and operationalize the principle of equal pay for work of equal value in Portugal. The preliminary results of the report were shared for feedback with the country's Commission for Equality in Labour and Employment (CITE) and the Portuguese social partners sitting on the Standing Committee for Social Dialogue (CPCS).