The role of the principal as leader has been a subject of considerable debate and research in education. This study examines the extent of variation in leadership behavior and activities among urban high school principals. Data were collected through interviews with principals and teachers in national samples of urban comprehensive high schools and magnet high schools. The findings show that the extent of principal leadership varies widely among both comprehensive and magnet high schools. Comprehensive high school principals tend to provide more leadership in administrative areas than in educational areas; only a small minority are highly rated on all of the measures. Almost half of the magnet high school principals provide strong leadership in all areas. The extent of principal leadership is also analyzed by differences in school and district contexts. References are included, along with an appendix showing the variable indicators in the survey of comprehensive high schools. (Author/TE)