This research investigated the impact of using manipulatives on 56 Grade 5 students’ (27 male, 29 female; age 10-11 years) mathematics achievement. A quasi experimental, action research design was utilized in which the experimental group was taught selected topics from the Number strand using manipulatives during a 3-week intervention, while the control group’s instruction did not include the use of manipulatives. Data were collected using a pre- and post-test and analysed using descriptive statistics and a Mann-Whitney U test. This analysis revealed that there was a statistically significant difference in the post-test performance of the two groups in favour of the experimental group. The effect size (r = .3) for this data was moderate. A significant difference was also found between the boys’ and girls’ post-test mathematics scores in the experimental group, with the girls outperforming the boys. A key implication of these findings is that since manipulatives were effective in significantly improving student achievement, its use could be extended and investigated further for other grade levels and mathematical topics. Strategies could also be adopted to address the disparity in performance based on gender in the sample.