The shortest summary of this thesis is in its title “Vitamin G”, where the G stands for the green space around us and Vitamin stands for the possible positive relationship between green space and people’s health. The aim of this thesis is to investigate whether green space in people’s living environment is positively related to their health. In the first part of this thesis we investigate the direct relationship between green space and health. Once a link can be established between green space and health, the next question is what mechanisms exist through which green space might exert a beneficial effect on health. In the second part of this thesis, therefore, we examine possible explanations for the relationship between green space and health. The third part focuses on exploring the relationship between green space and feelings of social safety, because green spaces are sometimes regarded as unsafe places. The fourth part of this thesis examines the question of whether health benefits conferred by green space are used in the health care sector, in order to find out whether the beneficial influence of green space is put into practice.