The purpose of this research is to find out whether the use of the Quizizz Application is effective or not in teaching English grammar and to find out the effect of the Quizizz application on the student to eleventh-grade students of SMP
Karya Budi Putussibau in the academic year 2021/2022.
The design was pre-experimental research in form of one group pre-test and post-test design. The population of this research was all eleventh-grade students of SMP Karya Budi Putussibau in the academic years of 2021/2022 and the sample chosen was VIII A consisting of 15 students. The sample was collected by cluster random sampling technique. The research was conducted at SMP Karya Budi Putussibau.
The technique of data collection applied in this research was the measurement technique. The data were collected through multiple choice questions in the quizizz application. The data were analyzed by using descriptive
statistics. The researcher used the data distribution. Since the data was normal the researcher used paired simple test analysis to test the hypotheses. The researcher's finding showed that Quzizizz was effective on students' English grammar; it was proved by the mean score during the pre-test and post�test was 33.0000 and 50.6667 which meant that there were differences before and after treatment. The SD of the pre-test (14.11686) was higher than the SD of the
post-test (17.30676). It showed that the treatment was well implemented. Lastly, it was proved by paired sample t-test value, the sig value was smaller than (0.002 < 0.05) which meant that Ha was accepted.

Keywords: Effectiveness, Quizizz, and Pre-experimental Research