This study examined the role that sex-related differences in the nature of the grade criterion and in variables associated with academic performance play in the over- and underprediction of college grades by the SAT when the test is used alone and in combination with high school grades. An entire freshman class at a large state university was studied. Women's GPA was underpredicted but only by a small amount. Adjusting the GPA for differences in grading standards for individual courses did not affect the underprediction, but controlling for sex differences in individual-difference variables concerned with academic preparation, studiousness, and attitudes about mathematics reduced or essentially eliminated it. (56pp.)