The present study aimed to explore the structural relations among teacher support, self-transcendence value, mastery goal, and academic achievement for high school students, with a special focus on the roles of self-transcendence value and mastery goal in the relationship between teacher support and academic achievement. For this purpose, the data on Korean high-school students from Programme for International Student Assessment (PISA) 2018 were analyzed using multilevel structural equation modeling, taking into account students nested within schools. The main results were as follows. First, at the student as well as the school levels, the direct effects of teacher support on academic achievement were not statistically significant, while the indirect effects of teacher support through the self-transcendence value and mastery goal were. Specifically, at the student level, teacher support showed positive indirect effects through the self-transcendence value and mastery goal on academic achievement. At the school level, teacher support showed a positive indirect effect on academic achievement only through the self-transcendence value. Second, teacher support had positive direct effects on the self-transcendence value and mastery goal at the student and school levels. At the same time, there were positive indirect effects of teacher support through the self-transcendence value on the mastery goal. Third, the self-transcendence value showed positive direct effects on the mastery goal at the student as well as the school levels. Fourth, the effect of the mastery goal on academic achievement was positively significant at the student level but not at the school level. These results confirm the important roles of the altruistic self-transcendence value and a learning-focused mastery goal in relation to teacher support and student achievement. In addition, the results suggest that teachers’ warm support and care should be provided in order to improve students’ self-transcendence value and mastery goal.