The purpose of this study was to examine the relationships between student engagement and academic achievement. In another saying, this study aimed at determining the extent to which student engagement explains or predicts academic achievement. The study was carried out with the correlational research. The research sample was made up of 304 students. Student Engagement Scale and Demographic Variables Form were used for data collection tools. For the analysis of the data, descriptive statistics, correlation analysis, twostep cluster analysis, independent samples t-test and regression analysis were applied. The results obtained via the analyses conducted revealed that there were significant relationships between the students’ academic achievement and student engagement as well as between their academic achievement and especially the dimensions of cognitive engagement, behavioral engagement and sense of belonging. In addition, it was found out that cognitive, behavioral and emotional engagements - that is class engagement - predicted academic achievement and explained it with a rate of 10%.