The effects of the school psychological environment on student motivation and the indirect effects of school leadership on student motivation are examined in this report. Path analysis of a comprehensive data set of over 16,000 fourth-, sixth-, eighth-, and tenth-grade students from 880 public schools was used to develop a causal model based on a psychometric approach. The model identifies a causal chain of factors leading from school goal stresses through motivation to achievement for grades 6, 8, and 10. Findings point to the importance of the school psychological environment at the tenth-grade level, especially for nonwhite students, the significance of ethnicity in motivation, and the crucial role of the family at the fourth-grade level. A conclusion is that school leaders can and do influence the psychological environment of their schools. Three figures and six tables are included. (39 references) (LMI)