This study sets out to examine schools principals' perception of the importance of school-based management (SBM) and instructional leadership tasks and their assessment of the performance of those tasks in Swedish upper secondary schools. A review of the literature on SBM and instructional leadership results in a list of twenty one tasks grouped into administrative, firefighting, and instructional leadership. Analysis of the survey responses from 234 principals shows that 80% of administrative and 75% of firefighting tasks were seen as highly important and performed well, while 68% of instructional leadership tasks were perceived as of having lower importance and performance. Implications for school principals and policy-makers are discussed and venues for future research are outlined.