One Hundred and Twelve Latino students from Philadelphia participated in this study, which examined the development of deductive reasoning across adolescence, and the relation of reasoning to test anxiety and standardized test scores. As predicted, 11th and ninth graders demonstrated significantly more advanced reasoning than seventh graders. Error response patterns revealed a steady, age-related increase in the ability to use falsification strategies. Test anxiety was not related to reasoning performance. These results are discussed in terms of developmental theories of deductive reasoning. Negative correlations between deductive reasoning and standardized test scores for 11th graders are discussed in light of accountability standards required by the No Child Left Behind Act. (Contains 3 tables.)