Examines educational attainment as a dimension of assortative mating. Barriers to marriage between persons with unequal amounts of formal schooling increased between the 1930s and the present. These increases may be the result of trends in average educational attainment, age at leaving school, and age at marriage. The degree to which schools affect the selection of marriage partners is dictated by the degree to which leaving school and marriage occur closely together and by the educational attainments of marriage partners. Variation in the average age at leaving school and marriage and in educational attainment induce variation in educational assortative mating. Trends in age at marriage affect both the structure of marriage and inequality within and between generations.