The study utilized a post-test-only, no-control experimental design to investigate the influence of sex-related contextual nature of tasks and perceived difficulty of these tasks on logical reasoning among 70 randomly selected high schools pupils (35 boys and 35 girls) in Nigeria. Three categories of tasks were used-those whose context were male related, those whose context were female related, and those that were relatively content-free. Results of the study show that males scored higher than females on male-related tasks and females scored higher on female-related tasks. No significant difference, however, was observed on the relatively content-free tasks. The need to design problems and tasks that are relatively nonsex-related is discussed.