Modernization theory argues that, as societies industrialize and further develop, the influence of social background and other ascribed characteristics on educational and socioeconomic outcomes declines, while achievement in the education system becomes more important. The purpose of this research is to investigate propositions derived from modernization theory as they apply to Australian society during the second half of the 20th century. Specifically, these are: (1) declines in the influence of socioeconomic background on education, occupation and earnings; (2) increases in the occupational and economic returns to education; and (3) decreases in gender inequalities in all three outcomes. These propositions are examined using data from nationally representative surveys conducted from 1965 through 2005. In accordance with modernization theory, it was found that the effects of socioeconomic background on education, occupational attainment and earnings have declined. Gender inequalities in education have been reversed, and the gender gap in earnings has declined. The effect of education on occupational attainment has increased more strongly among men than women. Contrary to expectations from one interpretation of modernization theory, the returns in earnings from education have not increased. (Contains 10 notes, 5 tables, and 1 figure.)