Background: Using meta-analytic review techniques, this study synthesized the results of 79 unpublished studies about the nature of transformational school leadership (TSL) and its impact on the school organization, teachers, and students. This corpus of research associates TSL with 11 specific leadership practices. These practices, as a whole, have moderate positive effects on a wide range of consequential school conditions. They also have moderately strong and positive effects on individual teachers' internal states, followed by their influence on teacher behaviors and collective teachers' internal states. TSL has small but significant positive effects on student achievement. Research Design: This synthesis of unpublished research results is accomplished by a systematic series of meta-correlations and is compared with the results of earlier systematic reviews of published TSL research. Findings: Among the conclusions arising from the study is that several of the most widely advocated models of effective educational leadership actually include many of the same practices. Conclusions: More attention by researchers, practitioners, and researchers needs to be devoted to the impact of specific leadership practices and less to leadership models. (Contains 6 tables and 10 notes.)