This study explores whether or not intelligence tests' scores predict individual differences in scholastic achievement irrespective of SES factors such parents' income and education. The variables of interest are analyzed considering three independent samples of participants comprising a total of 641 children. The participants belonged to a Brazilian School characterized by broad and representative ranges in intelligence, scholastic achievement, and SES factors. The results indicate that SES factors do not predict children differences in scholastic achievement, whereas children's intelligence tests' scores predict their scholastic differences. These results underscore personal intelligence as a genuine predictor of individual differences in scholastic achievement. © 2006 Elsevier Inc. All rights reserved.