A questionnaire was administered to school principals (N = 88). The questionnaire data, along with student achievement data and school practices data, were analyzed using hierarchical multiple regression to investigate the relationships among leadership preparation practices, self rated leader behavior, the school learning environment, and student achievement. After controlling for demographic variables, the amount of variance explained was incremented a statistically significant degree between: preparation practices and leader behaviors (R[superscript 2] = 5%); preparation practices and student achievement (R[superscript 2] = 5%); preparation practices and leaders' instructional knowledge (R[superscript 2] = 6%); and leaders' instructional knowledge and instructional practices in schools (R[superscript 2] = 5%). These findings suggest the further inclusion of the essential practices defined in this study into leadership preparation programs. (Contains 1 figure, 8 tables and 12 footnotes.)