This paper, prepared as a chapter for the "Handbook of Research on Teaching" (third edition), reviews correlational and experimental research linking teacher behavior to student achievement. It focuses on research done in K-12 classrooms during 1973-83, highlighting several large-scale, programmatic efforts. Attention is drawn to design, sampling, measurement, and context (grade level, subject matter, student socioeconomic status) factors that must be considered in interpreting this research and comparing the findings of different studies. Topics covered include: (1) opportunity to learn/content covered; (2) teacher expectations/role definitions/time allocations; (3) classroom management/student engaged time; (4) success level/academic learning time; (5) active instruction by the teacher; (6) group size; (7) presentation of information (structuring, sequencing, clarity, enthusiasm); (8) asking questions (difficulty level, cognitive level, wait-time, selecting respondents, providing feedback); and (9) handling seatwork and homework assignments. (Author/JD)