In this study, self-reported achievement, achievement-related behaviours, and achievement-related attitudes of 1,434 students attending secondary schools in Trinidad were examined. Females reported higher achievement than males, and males reported cutting class more than females, and both of these differences yielded medium effect sizes. Females also reported completing homework more frequently and higher academic perceived life chances than males. East Indian students reported higher achievement, homework completion, time on schoolwork, and academic perceived life chances than their Black and Mixed counterparts, as well as spending less time with friends during the week and lower rates of cutting class. However, all of the ethnic comparisons yielded low effect sizes. Given the differences found and the potential for achievement differences to increase over time, more research on gender and ethnic group differences is recommended.