The development of political thinking during adolescence was studied by interviewing 463 suburban and urban schoolchildren of average intelligence in grades 6, 8, 10, and 12. Each subject was interviewed individually by means of a Piaget-type questionnaire. Analysis of the questionnaire responses revealed a very distinctive developmental pattern. Younger subjects tended to have an authoritarian and restrictive concept of government and were largely unaware of broader political issues. Older subjects had a much more facilitative and democratic view of government and were relatively sophisticated about political problems. There was also, however, some evidence of increased political alienation with increasing age. Although there were minor sex, race, and area differences, the developmental differences were far more striking, appearing on almost every item of the questionnaire. The author concludes that except for being somewhat uninformed about the functioning of political parties, the average 12th grader is well-equipped to exercise his franchise. It is suggested that the public school system may play an important role in bringing about the observed results. (Author)