Very young adolescents (VYAs) between the ages of 10 and 14 represent about half of the 1.2 billion adolescents aged 10–19 in the world today. In lower- and middle-income countries, where most unwanted pregnancies, unsafe abortions, maternal deaths and sexually transmitted infections occur, investment in positive youth development to promote sexual and reproductive health (SRH) is increasing. Most interventions, though, focus on older adolescents, overlooking VYAs. Since early adolescence marks a critical transition between childhood and older adolescence and adulthood, setting the stage for future SRH and gendered attitudes and behaviours, targeted investment in VYAs is imperative to lay foundations for healthy future relationships and positive SRH. This article advocates for such investments and identifies roles that policy-makers, donors, programme designers and researchers and evaluators can play to address the disparity.