Democratic responsibility can be acquired only through practice and involvement. It does not arise suddenly in adulthood through simple maturation; it must be fostered directly from an early age.I believe that the environments we occupy as children and the extent to which we feel involved in shaping them, or caring for them, is a particularly important domain for such learning. Motivating the following account is the general conviction that genuine participation, involving the responsible sharing of power, is critical to the achievement of democracy. What this means for children’s participation is an important question for all of us who work with children, whether in research or in practice. This chapter is a beginning attempt to answer this question. It outlines the benefits of children’s participation in environmental planning and design and summarizes what we know from psychology and other disciplines as a beginning guide to the practice of this all-too-rare activity.