This study investigated whether the interaction of teacher, student, and classroom characteristics has a significant effect on classroom climate. Linear regression techniques were used to predict selected scales of "Anderson's Learning Environment Inventory" (LEI) from sets of orthogonal variables which are representative characteristics of the teacher, student group, and class structure. Eight scales accounted for 21-63 percent of the variance for the model group of 72 classes. Data for the study were drawn from the Harvard Project Physics Summative Evaluation Data Bank which represents a true national random sample of 54 physics teachers with 3,085 students in 103 classes. (Author/MLH)