This study investigated secondary school sixth, seventh and eighth graders' self-efficacy beliefs, engagement and disaffection in Math lessons and academic achievement in relation to learning Mathematics and Math performance. The study was conducted with the voluntary participation of 651 sixth, seventh and eighth graders attending secondary school. Research data were collected with the help of 'Engagement and Disaffection Scale', 'Self-Efficacy sub dimension' of 'Motivation Scale' related to learning and performance and students' Math first semester grades. It was identified in the study that students' self-efficacy beliefs in learning and performance in Math significantly and positively predicted their Math achievement. Behavioural and affective disaffection in Math lessons were found to predict Math achievement negatively. It was determined in the study that students' self-efficacy beliefs related to learning and performance in Math significantly predicted their behavioural and affective engagement in Math positively while predicting their behavioural and affective disaffection negatively.