<p>This study examines how parents’ beliefs about failure, specifically, whether failure is perceived as debilitating or as an opportunity for learning, are associated with adolescents’ relationships with teachers in lower secondary education. Drawing on research on parental belief systems and developmental perspectives on early adolescence, we propose that parental failure mindsets shape how parents interpret teachers’ competence, with implications for adolescents’ relational experiences at school. Using cross‑sectional data from 124 parent-student dyads, we assessed parental failure mindsets, parents’ perceptions of teacher competence, adolescents’ perceived student-teacher relationships, and students’ academic achievement. Results showed that a failure‑is‑enhancing parental mindset was positively associated with student-teacher relationships, even after controlling for academic achievement. Patterns of association were consistent with an indirect pathway via parents’ perceptions of teacher competence, particularly among lower‑achieving students; however, these indirect effects should be interpreted cautiously, given the study design. Taken together, the findings suggest that parents’ mindsets about failure represent an important yet often overlooked contextual factor linked to adolescents’ relational experiences with teachers during a developmentally sensitive educational phase. The study underscores the role of parental meaning‑making about failure and feedback during adolescence, particularly in efforts to strengthen parent-school partnerships and supportive learning environments.</p>