An environmental factor of particular importance to children's physical activity levels appears to be the presence of parks and open space. Thus, in promoting children's health, school grounds merit consideration as a potential setting for intervention. This paper explores how "green" school grounds, which contain a greater diversity of landscaping and design features, affect the quantity and quality of physical activity among elementary school children. Teachers, parents and administrators associated with 59 schools across Canada completed questionnaires (n = 105). Analysis reveals that through greening, school grounds diversify the play repertoire, creating opportunities for boys and girls of all ages, interests and abilities to be more physically active. Complementing the rule-bound, competitive games supported by asphalt and turf playing fields, green school grounds invite children to jump, climb, dig, lift, rake, build, role play and generally get moving in ways that nurture all aspects of their health and development. Of particular significance is the potential to encourage moderate and light levels of physical activity by increasing the range of enjoyable, non-competitive, open-ended forms of play at school. Seen in this light, green school grounds stand to be an important intervention to be included in school health promotion initiatives.