Positive student–teacher relationships are related to students’ academic achievement and behavioural and emotional adjustment. How a student’s behavioural and emotional strengths are associated with these relationships and how the relationships influence students’ academic performance remains unknown. We examined this framework using a cross-lagged panel model with a group of Finnish students and their parents from Grade 5 to Grade 7. The results revealed that the parents rated behavioural and emotional strengths are stable over a 1-year (r = .78) and 2-year (r = .71) period and that students’ perceptions of student–teacher relationships demonstrated greater change over time (r’s = .54, .35). Behavioural and emotional strengths demonstrated a positive relationship with student–teacher relationships as well as academic achievement (β = .39, p < .01). Strengths were also indirectly associated with academic achievement via student–teacher relationships. Study limitations, implications and future research are discussed.