In this study we examined the reliability and validity of global, mathematics and English self-concept scores from the Self-Description Questionnaire II (SDQ-II, Marsh, 1990b) in a random sample of 870 secondary school students in Trinidad and Tobago. The results provided strong evidence for the structural validity of the scores and yielded reliability estimates in the moderate to high range. There were no differences across gender and ethnic subgroups and a single grade level difference was found. The authors concluded that SDQ-II scores are useful for screening purposes, and in some cases individual decision making, in this population and recommended that the scores be examined for convergent and discriminant validity. (Contains 1 note and 1 table.)