This study aimed to determine the impact of concrete-pictorial-abstract (CPA) approach with collaborative lesson research (CLR) on Year Four pupils’ proficiency in volume. The counterbalanced research design, which consisted of three different groups of year four pupils with three treatments applied to each group, was used with the Proficiency in Volume Test (PVT) administered before and after each of the three CLR cycles. Cluster sampling was used to select three groups of 115 Year Four pupils consisting of 59 males and 56 females. PVT consisted of five questions based on the five strands of proficiency in volume: Q1 (conceptual understanding), Q2 (procedural fluency), Q3 (strategic competence), Q4 (adaptive reasoning), and Q5 (productive disposition). It has a total score of 15 and the indicators of proficiency in volume are low proficiency (0–4), average proficiency (5–10), and high proficiency (11–15). The data were analysed using the paired-sampleCLR cycles-test and one-way ANOVA in SPSS version 24. The results of the paired-sample t-test showed that there was a significant difference between the mean scores of the pre- and post-tests for each CLR cycle. The results of the paired-sample t-test for cube in the first, second and third cycles of CLR were: t = –6.74, df = 37, p < 0.05; t = –19.82, df = 37, p < 0.05; and t = –22.10, df = 38, p < 0.05, respectively. The results of the paired-sample t-test for cuboid in the first, second and third cycles of CLR were: t = 3.15, df = 37, p < 0.05; t = 9.87, df = 38, p < 0.05; and t = 20.76, df = 37, p < 0.05, respectively. The results of oneway ANOVA showed that there was a significant in the post-test mean scores between the first, second and third CLR cycles. The result of one-way ANOVA for cube was F (2,112) = 53.32, p < 0.05, while for cuboid it was F (2,112) = 71.16, p < 0.05. The CLR cycles carried out helped teachers in developing better teaching plans based on the CPA approach as well as enhancing Year Four pupils’ proficiency in volume.