This paper documents the widely perceived but little investigated notion that teachers today are less qualified than they once were. Using standardized test scores, undergraduate institution selectivity, and positive assortative mating characteristics as measures of quality, evidence of a marked decline in the quality of young women going into teaching between 1960 and 1990 is presented. In contrast, the quality of young women becoming professionals increased. The Roy model of selfselection is used to highlight how occupation differences in the returns to skill determine average teacher quality. Estimates suggest the significance of increasing professional opportunities for women in affecting the decline in teacher quality.