The aim of this study is to determine the relationship between students' use of tablets or computers in science classes and their science achievement. The study used the relational questionnaire method, one of the quantitative research methods, to examine the relationship between computer use and science achievement. This research sample group consists of students from 3 different countries who participated in the TIMSS 2019 exam in the 8th grade. Thirty-nine countries in grade 8 have participated in the TIMSS 2019 exam. Out of these 39 countries, three countries were selected in two stages and were included in this study. These are Singapore from high achieving level, Turkey from medium level and Georgia from low achieving countries level. The data of the study were obtained from the student questionnaire and the science exam results of the students using the TIMSS 2019 database, which is open to everyone. The question of "How often do you use a computer or tablet for school work (classroom tasks, doing homework, and outside classwork)?" was asked to students. The answers to this question have been examined. In the data analysis of this study, the multiple linear regression analysis technique, which is frequently used in quantitative research methods, was used. Findings revealed that as the frequency of students' use of tablets and computers increased, their science achievement decreased significantly. This decrease in student achievement was detected in all three countries included in the study.