This study investigates the associations between parental involvement and academic achievement across three criteria: school level (elementary and middle school), gender (male and female) and subject (mathematics and science). Additionally, it examines whether students' attitudes towards a subject and their academic aspirations mediate this relationship. A nationally representative sample of elementary and middle school children in Japan (1884 female fourth-grade students from 140 schools, 1849 male fourth-grade students from 139 schools, 1812 female eighth-grade students from 133 schools and 1789 male eighth-grade students from 131 schools) from the Trends in International Mathematics and Science Study 2011 was used for the analysis. The results show that parental involvement is associated with students' educational outcomes. Students' attitudes and aspirations mediate the associations between parental involvement and academic achievement. In particular, different associations between parental monitoring involvement and achievement are found for elementary and middle school.