This study examined the role of academic self-concept, mastery goals, and academic emotions as mediators in the relationship between perceived teacher autonomy support and student engagement in maths and literacy domains. Questionnaires completed by 854 students in Grades 4 and 5 in China show that perceived teacher autonomy support positively related to students' behavioural and cognitive engagement in learning both maths and literacy; however, the mechanisms of these relationships varied in the two subjects. When learning maths, perceived teacher autonomy support positively related to student engagement mainly through academic self-concept, mastery goals, and academic emotions; but when learning literacy, perceived teacher autonomy support directly related to student engagement and indirectly via academic self-concept. Moreover, enjoyment was more closely linked with maths engagement than literacy engagement. Findings contribute to understanding how teacher autonomy support influences maths and literacy learning and highlight the necessity to provide subject-specific guidance for future educational intervention.