Children are particularly vulnerable to the adverse health effects of tobacco smoke. Tobacco smoke exposure can cause harm from the earliest stages of life, leading to early pregnancy loss, congenital anomalies, preterm birth, intrauterine growth retardation, and perinatal death. Exposure during pregnancy and early life is furthermore associated with the development of asthma, severe respiratory tract infections, overweight, and behavioural disturbances. Tobacco control policies are effective in reducing tobacco consumption and second-hand tobacco smoke exposure. Through doing so, such policies have clearly shown to produce significant population health gains. Over recent years, a growing body of evidence demonstrates that children particularly benefit from tobacco control policies, even as these are primarily aimed at adults. In meta-analyses, introduction of smoke-free legislation has been associated with substantial drops in preterm births and hospital attendance for asthma attacks and severe respiratory tract infections among children. Similar effects, although less consistently, have been shown for increasing tobacco prices. Decreased exposure to other people’s tobacco smoke, both at home and in public places, as well as reductions in parental smoking, including during pregnancy, are the likely primary mediators of these effects. There is now a need to accelerate implementation of effective tobacco control policies to protect population health, including that of children. The observed health impacts on children constitute an important tool for advocacy, as children cannot protect themselves against tobacco smoke. Additional studies are needed to assess the effectiveness of tobacco control policies in low- and middle- income countries, and to evaluate the potential child health impact of newer policies including smoke-free car laws, plain packaging, and display bans.