The dissertation focuses on the effect of education on economic growth in Greece for the period 1928-1940. During the aforementioned period, we evaluate the influence of extra education on labor productivity. Improved education is translated into improved “quality” of labor, through the higher payments more educated employees earn in the workplace. We measure the impact of changes in quantity and “quality” of the workforce on GDP growth by constructing a standardization index. The quantitative investigation is backed up by a special reference to the educational reform of 1929. The Educational Reform succeeded in expanding the mass education in Greece, established mixed-sex schools (co-education), in order to increase the women’s work participation and exploit the payment differences (according to our calculations women’s average earnings were 65% of men’s earnings). The same reform promoted Vocational Education in Greece as well. In the main part of our research, given the data restrictions, we calculate indexes of human capital like adult literacy rates, gross enrollment rates, earning levels by educational attainment and the private returns to investment in Education for the period 1928-1940 in Greece. Consequently we present for the period 1935-1940 minimum and average wages of the most representative work groups. Additionally, we hand out original data on wages by educational level which are used to compile a standardization index. The index is used to measure the contribution of the increased workforce productivity (due to extra education) to the GDP growth. Given the limited amount of reliable data, we apply the Growth Accounting method and estimate that education accounts for 3,05% of GDP growth in Greece during the 1928-1940 period.