This study aimed to evaluate the effectiveness of the Mathematics Dictionary: Mathictionary in enhancing the mathematical vocabulary skills of Grade 6 learners at San Miguel Elementary School for the school year 2024-2025. Specifically, the research sought to assess learners mathematical vocabulary before and after the implementation of Mathictionary, a self-made supplementary learning material, and to measure its overall impact on the learners vocabulary proficiency. Using a quantitative research design, the study involved thirty-five purposively selected learners, who were identified as having the lowest scores in mathematics among a group of fifty-one participants. A pre-test was conducted to assess their mathematical vocabulary skills, followed by a post-test after utilizing Mathictionary. The results revealed a significant improvement in the learners vocabulary scores, with the post-test mean (83.00%) substantially higher than the pre-test mean (49.23%), indicating a shift from low to high proficiency in mathematical vocabulary. These findings suggest that Mathictionary is an effective tool for enhancing mathematical vocabulary skills. The study recommends the broader implementation of Mathictionary in schools and further investigation into its potential to foster critical thinking through higher-order thinking questions. This research provides valuable insights for educators and curriculum developers seeking to improve mathematical literacy and vocabulary among learners.