OBJECTIVE The current study tested whether adolescent children of alcoholics (COAs) showed poorer academic performance than did demographically matched controls, and whether such parent alcoholism effects varied as a function of heterogeneity within the COA sample. In addition, controlling for parent educational attainment, we examined whether relations between parental alcohol dependence and academic performance could be accounted for by COAs' lower levels of task orientation, heightened levels of environmental stress, lowered levels of family organization and less parental involvement in their school activities. METHODS A sample of 221 adolescent COAs and 196 demographically matched controls (53% boys, mean [+/-SD] age = 12.7+/-1.46 years), and their parents, were included in the current study. Adolescents were selected from a larger 3-year longitudinal study in which participants were interviewed three times at annual intervals. Those who were interviewed at Time 3 and who had academic achievement data were included in the current analyses. Demographic information and diagnoses of parental alcoholism were collected at Time 1, and data on potential mediators were collected at Time 3. Academic achievement data were collected at Time 3 from school records. RESULTS Multiple regression analyses indicated that COAs received lower school grades than did their non-COA peers (mean = 2.19+/-1.08 vs 2.54+/-1.01, respectively). COAs with two alcoholic parents (mean = 1.80+/-1.17) and COAs with at least one parent diagnosed alcohol dependent (mean = 2.01+/-1.01) showed particularly low grades. Parental alcohol dependence was also associated with lower math achievement scores (mean = 48.52+/-24.68 vs 62.47+/-26.71). Evidence indicated that adolescents' task orientation mediated the relation between parental alcohol dependence and adolescent grades (indirect effect, t = -2.93, 289 df, p < .01), and between parental alcohol dependence and adolescent math achievement (indirect effect, t = -1.99, 194 df, p < .01). Adolescents' life stress did not mediate the relations of interest after controlling for task orientation. CONCLUSIONS The current study confirmed that COAs, particularly those whose parents are alcohol dependent as opposed to having a diagnosis of alcohol abuse, achieve relatively lower academic outcomes in comparison to non-COA peers. Adolescent task orientation partially mediated the relations between parent alcohol dependence and academic achievement, indicating that academic difficulties in COAs may be partly due to impaired motivation and organization.