This study examined the impact of frequent of testing on study habits and achievement in mathematics among public secondary school students in Ogun State, Nigeria. Two out of the four research hypotheses postulated were accepted, whereas the remaining two were rejected. The findings showed that there were significant differences in the mean scores of students’ achievement in mathematics and study habits as a result of exposing students to varying test frequencies. In addition, the study revealed that gender is not a significant factor when planning to improve study habits and achievement in mathematics. On the basis of these findings, test frequency of every 2 weeks was recommended to improve students’ academic achievement in mathematics.