Gamification on English Vocabulary Acquisition: A Quasi-Experimental Study

English vocabulary acquisition is a critical foundation of second language learning, yet many urban public schools in the Philippines face challenges such as overcrowded classrooms, low student engagement, and limited instructional resources. This study examined the effect of gamification on English vocabulary acquisition among Grade 9 students in an urban public high school in Pagadian City. Using a quasi-experimental pretest–posttest control group design, 70 students were divided into an experimental group (n = 35) and a control group (n = 35). The experimental group received gamified vocabulary instruction using digital platforms such as Kahoot! and Quizizz, while the control group was taught using traditional methods. The intervention lasted for ten weeks. A 60-item Vocabulary Acquisition Test measuring receptive and productive skills (α = .90) was administered as a pre-test and a post-test. Results showed that both groups had comparable vocabulary levels before the intervention. After the treatment, the experimental group demonstrated a significant increase in overall vocabulary performance with a large effect size, while the control group showed only minimal improvement. Post-test comparisons revealed that students exposed to gamified instruction significantly outperformed those in the traditional group. Furthermore, gamification had strong positive effects on both receptive and productive vocabulary skills. The findings indicate that integrating game elements such as points, competition, and immediate feedback can greatly enhance student motivation, engagement, and vocabulary retention. Gamification, therefore, serves as an effective and practical strategy for improving English vocabulary learning in urban ESL classrooms. The study recommends the integration of gamified activities into regular English instruction and supports teacher training and policy initiatives that promote innovative, technology-based learning approaches.