Because various aspects of the school organization matter, this study was designed to determine to what degree principals in both charter and traditional public schools experience autonomy. This quantitative study draws on the 1999-2000 School and Staffing Survey, and the analyses suggest that there are variations in the degree and amount of principal autonomy experienced across charter and traditional public schools. Principals, although clearly autonomous, are constrained by state influence but supported by district influence. Charter school principals enjoy greater degrees of autonomy across various internal school activities, and this contributes to the conceptual understanding of organizational autonomy. (Contains 5 tables and 2 notes.)