The relationship between locus of control orientation and academic achievement has recently been questioned. To investigate the relationship between measures of locus of control, intelligence, and academic achievement, 58 normal and 50 delinquent 15-year-old adolescents were administered the Peabody Vocabulary Test, Nowicki-Strickland Locus of Control Scale for Children, and the Wide Range Achievement Test in reading, spelling, and arithmetic. Academic achievement was significantly related to locus of control only for normal adolescents, while intelligence test scores were significantly related to locus of control for both normal and delinquent groups, suggesting that locus of control is a function of intelligence rather than achievement. The finding that locus of control was ineffective in discriminating between normal and delinquent adolescents questions the utility of the locus of control construct for identifying clinical populations. (Author/NRB)