To extend previous research on adolescent temperament, this study developed and tested the Adolescent Temperament Questionnaire (ATQ), a 70-item self-report questionnaire which used a Likert-like scale and a wider array of items than used in previous assessment instruments. The study examined the conceptual fit of higher order structures of temperament to models of adult personality. These structures were based on an earlier study of infant development in which it was proposed that temperament consists of nine distinct dimensions including sensory threshold, intensity of mood expression, distractibility, persistence, adaptability, approach/withdrawal from new situations, regularity of biological functions, activity level, and positive and negative mood. The ATQ was administered to 436 students in middle and senior high school. Results of a factor analysis suggested that the structure of temperament in adolescence is multidimensional, although comprised of highly related factors. Moderately strong relations between first-order factors that tapped the second-order factors of Diligence and Sociability were found. Second-order constructs were moderately associated, suggesting substantial overlap among the behavioral styles they represented. Finally, factor loadings for Intensity, Threshold, and Distractibility were relatively low, indicating a lack of conceptual purity in these dimensions. (MM)