AbstractThis study was designed to determine the relationship among teacher classroom management behavior, student engagement, and student achievement of middle and high school science students. These variables were investigated across varying levels of academic aptitude. Two week long units were taught by 30 experienced science teachers. During this period of time teacher classroom management behavior, student achievement (n= 570), student engagement (n= 269), and student academic aptitude (n= 649) were measured. Twelve selected management indicators from Georgia Teachers Performance Assessment Indicators (TPAI) were used to measure teacher classroom management behaviors. Regression analysis was used to determine the relationship between the variables, and appropriatepost hocprocedures were used. Analyses showed that there was a significant relationship among all variables.Post hocanalysis showed that these results were consistent across levels of aptitude. Other relationships found were between student engagement and achievement, student aptitude and achievement, and student aptitude and engagement. Correlation coefficients were obtained for each individual management indicators. Those particular management behaviors which were correlated with achievement and engagement are: identifies students who do not understand directions and helps them individually, maintains learner involvement in lessons, reinforces and encourages the efforts of learners to maintain involvement, attends to routine tasks, uses instructional time efficiently, provides feedback to learners about their behavior, manages disruptive behavior among learners.