As Forest School has become more widespread throughout Britain an understanding is needed of its impact. This paper outlines a two-phase evaluation project undertaken in Wales and England from 2002 to 2005. The evaluation was undertaken through a partnership between Forest Research and the New Economics Foundation. A methodology was developed to explore the impacts of Forest School on children and this was then used to track changes in twenty-four children at three case study areas over an eight-month period. The research highlights that children can benefit in a range of ways. Six themes emerged from the data of the positive impacts on children in terms of confidence, social skills, language and communication, motivation and concentration, physical skills and knowledge and understanding. Two further themes highlight the wider impacts of Forest School on teachers, parents, and the extended family. Contact with the natural environment can be limited for children and young people in contemporary society due to concerns about safety outdoors and issues of risk and liability. Forest School provides an important opportunity for children to gain access to and become familiar with woodlands on a regular basis, while learning academic and practical skills. The constructivist theory of learning seems to be particularly suited to the Forest School approach as children make meaning from their direct experiences. The participatory action research approach taken in this study promoted reflective practice amongst the stakeholders involved and provided them with a sense of ownership of the study, as well as an opportunity to learn from each other.