Based on a synthesis of unpublished transformational school leadership (TSL) research completed during the last 14 years, this study inquired into the nature of TSL and its effects on student achievement using review methods including standard meta-analysis and vote-counting techniques. Results identify a wider range of TSL practices than typically has been measured in previous TSL research. Results also suggest that TSL has small but significant effects on student achievement, some TSL practices are especially powerful explanations of these effects, and a large handful of variables both moderate and mediate TSL effects on students. (Contains 1 note and 6 tables.)