This study looked at the effect of both quantity and quality of computer use on achievement. The Program for International Student Assessment (PISA) 2003 student survey comprising of 4,356 students (boys, n = 2,129; girls, n = 2,227) was used to predict academic achievement from quantity and quality of computer use while controlling for demographic differences such as gender, race, and socioeconomic status. A weighted ordinary least squares hierarchical multiple regression approach was utilized. Both the quantity and quality of computer usage were found to be significant predictors of achievement. Implications were discussed. This study differs from past research in that it investigates the simultaneous effect of both quality and quantity of computer use on academic achievement in context of a large-scale probability sample which allows projection of our analytical results to the entire population of 15-year old high school students in the U.S.