Vocabulary mastery is crucial for individuals to effectively use language in verbal and written communication. This study aims to find out the effectiveness of using Scrabble games in improving the vocabulary mastery of eighth-grade students at SMP Hj. Isriati Semarang. Additionally, it seeks to explore the impact of implementing Scrabble games on vocabulary mastery and evaluate students' responses to this approach. The research employed a quasi-experimental design with a nonequivalent control group. The research instruments comprised tests and questionnaires. The findings revealed that the average pre-test score for the experimental class was 55.04, while the control class scored an average of 56.50. In the post-test, the experimental class obtained a mean score of 69.92, whereas the control class scored 54.83. The students' performance significantly improved from the pre-test to the post-test. Whereas the p-value (Sig. (2-tailed)) .000 less than alpha (0.05) or p<0.05. It led to rejecting the null hypothesis (H0) and accepting the alternative hypothesis (Ha). Furthermore, the questionnaire results indicated that most students strongly agreed or agreed with all statements, reflecting a positive attitude toward learning vocabulary through the Scrabble game method. It can be concluded that using Scrabble games effectively improves vocabulary mastery among Eighth-Grade students at SMP Hj. Isriati Semarang.