The aim of this monograph is to combine the knowledge from previous research on teacher competencies and their effects on students´ social, motivational processes, academic behaviour and their achievement with the authors´ own research. Therefore, the monograph starts with the model of effects teacher competencies can have on different processes in students, which is a framework for the theory and research described in later chapters. The model is followed by the synthesis of research findings related to a group of variables used in the research which can influence the students´ school achievement: teaching methods, students´ perceptions of teacher classroom management, social-motivational and cognitive processes. ... Individual chapters that follow are first related to specific elements and concepts of the proposed model and include a theoretic part as well as empirical results of two samples of eighth-grade primary school students and third-grade grammar school students in Slovenia. The chapters are first related to the concept of teacher competencies, then to teacher competencies as perceived by their students, followed by a discussion of the students´ motivation, learning behaviour and achievement and finally the teachers´ classroom management and development of the students´ social skills. The monograph concludes with the empirical synthesis in which path analysis models presenting the relations between all four sets of variables, namely perceived teachers´ competencies, students´ motivation, their academic behaviour and achievement are discussed, and with the final conclusions and implications for educational practice. (DIPF/Orig.).