As an important part of adolescents' social capital, teacher-student relationship (TSR) and parental involvement (PI) are important for student learning. However, we know little about how PI works with TSR in relation to adolescents' learning outcomes. The present study aimed to examine the association between TSR and adolescents' learning outcomes in China, as well as testing the potential moderating role of PI. Participants were 332 fourth graders and 321 eleventh graders from Shandong province, China. Student-perceived TSR and home-based PI, and curriculum-based measures of academic achievement were collected in October 2019. The major findings of the study included: (1) TSR and students' academic performance positively correlate with each other; (2) PI moderates the relationship between TSR and students' academic performance; (3) High PI in primary school reduces the impacts of lower TSR on student performance; (4) High PI in secondary school has no compensating effect on low TSR, but it still reduces the influence of TSR on academic performance. The present research verifies and extends the association between TSR and academic achievement to parental factors, and holds substantive theoretical and practical implications for teacher education and family education research.