In Portugal, over the last two decades, the proportion of women among employed workers increased from 35 to 45 percent. This evolution was accompanied by a sharp fall in the gender wage gap from 32 to 20 percent. The improvement in the wage outcome of the women, however, is fully accounted by the catching up of their skills in comparison to males, after two decades of human capital investments. By 2013 women already possess observable characteristics that enhance productivity identical to their male counterparts. This means that gender discrimination remained roughly constant over the 1991-2013 period. In this study, we investigate the sources of the wage gender gap and conclude that sorting among firms and job-titles can explain about two fifths of the wage gender gap.