Studies of past crises have demonstrated that adverse experiences during critical periods of human development hamper the individual’s ability to reach its full potential and leaves lasting marks on health, behaviour, productivity and society as a whole. The COVID-19 crisis has severely worsened the environment in which we live and in which our future generations are being shaped, and will lead to loss of future human potential and capital. It is clear that the COVID-19 pandemic does not only harm the current world population, but also affects our future, as well as that of future generations. The science of transgenerational plasticity demonstrates that investments in early life hold the promise of having beneficial effects across multiple generations. As governments are reopening societies and prioritising policies, their overarching goal should be to improve the environment in which future generations grow and develop, learn and live. This will change the lifetime trajectories of children for the better and affect future health, school success, behaviour, productivity and well-being. This prioritisation will prove to be the most effective intervention to build sustainable futures but will also yield returns many times the original investment. It is a promising way to break the intergenerational cycle of adversity and accelerate progress on achieving the Sustainable Development Goals.