 Adolescents face significant barriers to contraception access and utilization that result in adverse health effects of early pregnancy and childbirth. Unsafe abortions continue to occur partly due to failure to prevent pregnancies, with Sub-Saharan Africa contributing the most significant burden of all unsafe abortions among young people globally, of which a quarter occurs in those aged 15–19 years. We aimed to conduct a systematic review of the contraceptive and abortion knowledge, attitudes and practices of adolescents in low and middle-income countries to increase the understanding of the sexual and reproductive health dynamics that they face.