This study aims to examine the impact of gamified learning using Quizizz on English as a second language (ESL) learners' grammar achievement. The pre-/post-test control group design was applied to research 63 English-majored freshmen. 20 multiple-choice quizzes were designed based on grammar points included in the basic grammar course over a 10-week intervention period. There were 33 students from the experimental group doing the quizzes on Quizizz, while 30 participants from the control group did the same quizzes on paper. The findings indicate that although students from the two groups both improved their marks on the post-test compared to the pre-test, students from the treatment group got significantly higher scores than those from the control group on the achievement test. However, educators are supported to consider using this gamified learning platform as a supportive tool besides choosing the appropriate instructional content to optimize the quality of their teaching.