Background: Academic pressure is a potential contributor to adolescent mental health problems, but international evidence on this association has never been synthesised. Methods: We conducted the first systematic review on the association between academic pressure and adolescent depression, anxiety, self-harm, suicidality, suicide attempts and suicide. We searched MEDLINE, PsycINFO, ERIC and Web of Science (core collection) up to November 24, 2022, for studies of school-going children or adolescents, which measured academic pressure or timing within the school year as the exposure and depression, anxiety, self-harm, or suicidal ideation, attempts or suicide as outcomes. Risk of bias was assessed using the Mixed Methods Appraisal Tool. We used narrative synthesis to summarise the evidence. The review was prospectively registered with PROSPERO (CRD42021232702). Results: We included 52 studies primarily from Asia (n=26) and Europe (n=20). Most studies assessed mixed anxiety and depressive symptoms (n=20) or depressive symptoms (n=19). Forty-eight studies found evidence of a positive association between academic pressure or timing within the school year and at least one mental health outcome. Limitations: Most studies were cross-sectional (n=39), adjusted for a narrow range of confounders or had other limitations which limited the strength of causal inferences. Conclusions: We found evidence that academic pressure is a potential candidate for public health interventions which could prevent adolescent mental health problems. Large population-based cohort studies are needed to investigate whether academic pressure is a causal risk factor that should be targeted in school- and policy-based interventions.