The relationship between socioeconomic status and academic achievement was studied. Cross-comparisons were made of this relationship in terms of different racial-ethnic groups, various regions of the United States, and metropolitan-nonmetropolitan locations. Subjects were sixth, ninth, and twelfth graders from the North, the South, and the West. The study concluded that socioeconomic status is assuming increasing importance in school achievement for all students, and the achievement levels of high socioeconomic Negro students are lower in most instances than the achievement levels of low socioeconomic white students. Suggested explanations included the low educational level of most Negro parents and the differential dropout rates of racial and ethnic groups. A number of mediating factors were seen as possible causes of these results; therefore, caution must be exercised in trying to determine specific causal factors. References and tables are included. (RT)