objective This study aimed to determine the burden of depression, suicidal ideation and suicidal behaviour amongst adolescents at sites in six sub-Saharan African countries and examine associated risk and protective factors.methods Household-based cross-sectional study involving male and female adolescents ages 10-19 years. A total of 7,662 adolescents from eight sites in six countries participated in the survey. Three sites were urban: Dar es Salaam (Tanzania), Harar (Ethiopia) and Ibadan (Nigeria); five were rural: Dodoma (Tanzania), Iganga/Mayuge (Uganda), Kersa (Ethiopia), Ningo Prampram (Ghana) and Nouna (Burkina Faso). Log-binomials models were used to estimate relative risks and confidence intervals for factors associated with depression and suicidal behaviour. This was supplemented using log-Poisson models as needed.results The prevalence of suicidal behaviour over the last 12 months ranged between 1.2% and 12.4% in the eight sites. Depressive symptoms and suicidal ideation/behaviours were associated with older age, female sex, food insecurity, poor access to health care and substance use. Depression was strongly associated with increased risk of suicidal behaviour at two sites where the multivariate model converged: Harar, Ethiopia (RR = 3.5, 95% CI 1.8, 7.0, P < 0.05) and Ibadan, Nigeria (RR = 3.7, 95% CI 2.2, 6.3, P < 0.0001).conclusions Depressive symptoms and suicidal behaviour are common amongst sub-Saharan African adolescents at these 8 sites. Most factors associated with depressive symptoms are modifiable and preventable. Routine screening for depressive symptoms in services frequented by adolescents in these and similar communities would be crucial in early detection and prompt intervention.keywords depressive symptoms, suicidal behaviour, adolescents, sub-Saharan Africa, ARISE Sustainable Development Goals (SDGs): SDG 1 (no poverty), SDG 2 (zero hunger), SDG 3 (good health and well-being), SDG 5 (gender equity), SDG 8 (decent work and economic growth), SDG 10 (reduced inequalities), SDG 17 (partnerships for the goals)