The ongoing urbanisation worldwide has led to an increasing number of children living in urban areas. Urban children, compared to children from rural areas, are generally exposed to higher levels of a number of environmental hazards such as air pollution, noise and heat, and have limited access to natural environments, including green spaces. At the same time, urban lifestyle is predominantly associated with lower levels of physical activity and higher exposure to crime and psychological stress. Contact with green spaces, on the other hand, is thought to have a defining role in human brain development. An accumulating body of evidence has also associated such contact with improved mental and physical health in children. This chapter aims to present a synopsis of the current state-of-the-art of research linking green space and child health and development. Towards this aim, we (1) elaborate on potential mechanisms underlying health effects of green spaces, (2) highlight the importance of prenatal and postnatal periods as windows of vulnerability, and (3) provide an overview of the available evidence on effects of green spaces on (a) pregnancy outcomes, (b) brain development including structural brain development, as well as behavioural and cognitive development, (c) respiratory and allergic conditions, and (d) cardiometabolic risk factors.