This evaluation of United World Colleges (UWC) explored the relationships between the movement's aims and the processes and outcomes of learning in the colleges. The purpose of the evaluation was to establish how efffective the colleges were in meeting their aims and the factors that defined their effectiveness. The research focused on the perspectives of UWC students, graduates and staff in eight of the nine UWCs internationally. Semi-structured interviews provided the main source of evidence in the first phase of data collection, supplemented by student journals, informal observations and documentary evidence. The second phase of data collection comprised a large-scale postal questionnaire on UWC students to check the validity of initial findings amongst a larger sample. The evaluation established that UWCs were effective in meeting their aims, especially in relation to citizenship education. Howvever, while it was apparent that the normal curriculum was an important and often underestimated factor or influence, it became clear that informal learning experiences were more influential. These experiences were related to the way in which individuals interacted with day-to-day activities and with one another and hence much of what could be understood about the effectiveness of UWCs appeared to he rooted in how the colleges functioned as communities. By exploring the cultural norms that governed communal behaviour, it was possible to identify certain values and beliefs shared within and between UWCs. These values and beliefs could be traced back to the movement's founding principles and appeared to be the essence or its culture, providing the learning experiences encountered in its colleges with meaning and potency.