This study aimed to determine the affective and socioeconomic variables significantly predicting achievement level of low- and high-achieving students. The data of 1323 low-achieving and 2022 high-achieving Turkish students participated in the PISA 2015 were used in the study. The data were analyzed by using binary logistic regression. The findings showed that test anxiety; achievement motivation; enjoyment of cooperation; environmental awareness; environmental optimism; science self-efficacy; epistemological beliefs; economic, cultural and social status index (ESCS), and the information and communication technology (ICT) resources index were significant predictors of the achievement level of low- and high-achieving students. While test anxiety and environmental optimism scores of low-achieving students were higher, achievement motivation, enjoyment of cooperation, environmental awareness, science self-efficacy, epistemological beliefs, ESCS, and ICT resources scores were higher among high-achieving students.