The purpose of this study is to develop and evaluate the effectiveness of DoCtor WoRM’s Module in improving multiplication skills among Year Four low achievers in National-Type Chinese Primary School (SJKC). DoCtor WoRM’s Module had been designed based on Constructivist Theory, mastery learning, and game-based learning. The module was developed based on Sidek’s Module Development Model. Quantitative approaches with quasi-experimental design were used for this study. A number of 60 Year Four low achievers from Manjung District were selected using random sampling. The sample was divided into the treatment and control groups. The former went through a teaching and learning process using DoCtor WoRM’s Module, while the latter learnt through traditional teaching. After the pre-test, three months of intervention was carried out to both groups of sample, followed by a post-test. Data was analysed using descriptive and inferential statistics. Dependent t-test showed that there was a significant increase in the achievement of treatment group from pre-test (M = 59.47, SD = 27.242) to post-test (M = 91.53, SD = 12.566), t(29) = 6.254, p < .001. The independent t-test had shown that the achievement of multiplication skills in post-test of treatment group (M = 91.53, SD = 12.566) is higher than the post-test of control group (M = 79.17, SD = 22.588), t(58) = 2.621, p < .012. As a conclusion, DoCtor WoRM’s Module has improved the multiplication skills among Year Four low achievers in SJKC. This study implicates that DoCtor WoRM’s Module should be applied to the low achievers in Malaysia in order to improve their Mathematics achievement particularly in multiplication skills.