Abstrak
The purpose of this study is to determine the effectiveness of using Quizizz on the vocabulary mastery of seventh-grade students at SMPN 4 Padang Panjang. Teacher face difficulties in selecting appropriate learning media due to technological limitations that affect students' vocabulary mastery. Students are more enthusiastic about learning that actively involves them and is supported by technology-based media. In addition, low motivation and high embarrassment sometimes become concurrent problems that often limit their participation in using vocabulary in class. This study uses a quantitative descriptive method with two classes (VII.1 and VII.2) as samples, consisting of 64 students. The instrument used in this study is a questionnaire, while students' vocabulary scores are used as evidence of an increase in vocabulary mastery after implementing Quizizz. The data are analysed using percentage, mean, median, and mode calculations. The results show that Quizizz is very effective in improving students' vocabulary mastery, with an overall effectiveness rate of 89%. Class VII.1 achieves an effectiveness rate of 86% (effective), while class VII.2 achieves 91% (very effective). The students' vocabulary scores before and after the implementation of Quizizz show a significant increase, proving an improvement in vocabulary mastery. It can be concluded that Quizizz is an effective educational game as a learning medium, which is able to increase students' activity, participation, and motivation in vocabulary mastery.