This study examined how self-efficacy beliefs, a central construct of social cognitive theory, might be used to inform educational leadership and policy decisions related to school accountability measures. A survey of 112 principals in Florida was used to investigate the degree to which principals believed the goals of federal and state school accountability measures (the No Child Left Behind Act of 2001 and the Florida School Grades Plan) were actually attainable, and to what degree they believed their leadership actually helped achieve these goals. A large majority (83.8%) of respondents believed the state goals to be attainable, whereas only a minority (20.7%) believed the federal goals could be attained. This disparity was associated with a significant difference in self-efficacy beliefs related to the plans, and in the associated leadership behavior of principals. This significant difference in principal self-efficacy beliefs could predict a disparity in leadership effort toward goal attainment. The study suggested that policymakers should be cautious about revising the goals of the Florida School Grades Plan, since principals' self-efficacy beliefs related to the plan were already quite high. In contrast, the findings suggested that policymakers should look to revising the goals of the No Child Left Behind Act of 2001 to correct the dearth of principal belief in the actual attainability of its goals.