<![CDATA[General Background: Vocabulary is essential in mastering English, especially at the elementary level, where it forms the basis for communication. Specific Background: However, Indonesian fifth-grade students often struggle with vocabulary acquisition due to uninspired and rote-based learning methods, especially in rural schools. Knowledge Gap: While gamified applications like the English Vocabulary Application (EVA) have shown promise in urban secondary contexts, their impact on rural elementary students remains underexplored. Aims: This quasi-experimental study investigated the effectiveness of EVA in enhancing vocabulary mastery among fifth graders at SD Negeri 10 Jarai. Results: The experimental group using EVA significantly improved from a pre-test mean of 54 to a post-test mean of 85, surpassing the control group's improvement, which began at a higher baseline. Statistical analysis confirmed significant differences favoring the experimental group (t-obtained = 10.5860; p < 0.05), with a very large effect size (Cohen’s d = 1.63). Novelty: This study uniquely applies a gamified mobile application in a rural elementary setting using a quasi-experimental design. Implications: Findings support the integration of mobile-based learning tools like EVA to boost engagement and consistency in vocabulary learning in underserved educational environments.Highlight : Interactive Strategies: The study applied games and contextual learning to enhance vocabulary retention. Improved Outcomes: Students showed higher test scores and increased engagement after the intervention. Early-Level Focus: Emphasizes the importance of innovative methods for vocabulary development in primary education. Keywords : Vocabulary Mastery, English Learning, Fifth Grade, Classroom Action Research, Elementary Education]]>
