The study investigated the influence of gender, course of study and numerical ability (independent variables) on secondary school students' achievement in Practical Geography (dependent variable). Purposive sampling was used to select four co-educational secondary schools established in the same year. A sample of 367 Geography students (157 females and 210 males) in their final year (SS 3) was involved in the study. Using three instruments, the Practical Geography Achievement Test, Numerical Ability Test and a student questionnaire, the data collected were subjected to t test, Levene's test and univariate ANOVA. The findings did not reveal significant differences in female and male performances in the PGAT, whereas students' achievement in the PGAT was differentiated by their course of study and numerical ability. Interestingly, the impact of students' numerical ability on their achievement in Practical Geography is not significant across students' gender and course of study. However, there is a need to examine why gender should differentiate students' achievement in some subject areas and not in others.