The study investigated the influence of gender, school location, and socio-economic status (SES) on students' academic achievement in mathematics. The study was an ex-post factor design in which the variables were not manipulated nor controlled. Four research questions and three hypotheses were formulated to guide the study. The stratified random sampling approach was used to sample 1900 students such that the variables in the study were put into consideration. Two instruments were used for this study namely mathematics objective test (MOT) and socio-economic status questionnaire (SESQ). Experts in mathematics and measurement validated the instruments. The reliability of the MOT and SESQ using the test-retest method of establishing reliability yielded 0.71 and 0.70 respectively. The results of the study showed that students have an average achievement in mathematics. The result also showed that male students performed better than female students, urban students performed better than rural students and students of parents with high SES performed better than students of parents with low SES. One of the recommendations was that teachers should put into consideration the disparities that exist between male/female, urban/rural, and low SES/high SES when teaching mathematics.