The Every Child Succeeds Act of 2015 signaled a shift toward the recognition of the importance of school leadership, reflecting a growing body of literature that demonstrates principals are second only to classroom instruction in supporting student success. This influence is the greatest when principals focus on teaching and learning, or instructional leadership. The ability to focus on instructional leadership requires knowledge, as well as the schema that creates mental models for instructional leadership tasks. This study draws on interviews with principals to examine the relationship between their theory of leadership, which are conceptualized as leadership schema, and their instructional leadership practices. The findings suggest that there are similarities in the instructional leadership tasks undertaken by principals, but that how they engage in tasks is partially determined by their theory of leadership.