Learning to read, talk, write, and listen requires a strong vocabulary which is essential to be able to communicate and convey feelings clearly may it be written or spoken. This is why learners need to acquire an extensive range of vocabulary for academic and personal success; thus, this study used the concept cube strategy to improve the vocabulary skills of Grade 4 pupils in English. Utilizing the experimental research design, two groups -control and experimental -were treated in the study, each with thirty participants. The research data were collected through the use of researcher-made pretest-posttest questionnaires. Mean and standard deviation were used to determine the performance level of the participants and an Analysis of Covariance was used to identify the significant difference between the performance level of the control and experimental groups. The results showed that the participants in the control group performed at an “Intermediate” level while the experimental group achieved the “Proficient” level after the intervention was implemented. There also existed a significant difference in the performance level between the two groups. The results, also, affirmed that the use of the concept cube strategy was effective in enhancing the vocabulary skills of the Grade 4 pupils in English.