Rational-Emotive Therapy states that maladaptive behaviors and emotional problems are the result of certain irrational beliefs that people hold and a number of empirical investigations with adult subjects have supported this claim. To determine whether the relationship between irrationality and psychological adjustment holds for adolescents, one hundred and eighty-four boys in the seventh, ninth, and twelfth grades were administered the Common Beliefs Survey III, to measure irrational beliefs, and the Neuroticism Scale Questionnaire. The advisors of each of the boys were also asked to rate the boys on the Behavior Problem Checklist. Data analysis revealed that the developmental trends for the irrational beliefs were generally different from those for neuroticism and behavior problems. The results suggest that the scales for irrational beliefs, neuroticism and behavior problems are not measuring the same entity during adolescence. These results were confirmed by correlational analyses since very few significant positive correlations were found among the scales. (Author)