The development of students'' self-determination influences their academic intrinsic motivation and achievement.Yet, there are no known studies addressing these issues in Ethiopia. Thus, the writer of this book investigated the extent and the process model relationships of teachers'' behaviors in raising students'' self-determination, academic intrinsic motivation, and academic achievement at primary school level. The book reveals that teacher behavior has a significant direct and mediated effect on students'' academic intrinsic motivation via students'' self-determination. Teacher behavior was significantly related to students'' self-determination and it in turn was significantly related to students'' academic intrinsic motivation. However, students'' self-determination and academic intrinsic motivation were not significantly related to their academic achievement. Therefore,the findings of the study could shade light to teachers, parents, and educational decision makers in improving self-determination, academic intrinsic motivation, and achievement of children.