Designed to provide data establishing the effects of individualization, teacher directiveness, and learner support on reading achievement, this study utilized 118 first-grade classrooms representing 44 schools located in suburban, rural, city, and inner city areas. Measurement of the three dimensions of the classroom environment was achieved through a dichotomization of observational data into high and low categories. Descriptive data revealed first-grade classrooms to be generally characterized by teacher directiveness, a substantial amount of learner support, and limited individualization. Student outcome measures of reading achievement from 67 classrooms revealed that significant differences existed between the two teacher-directed groups, with low teacher directiveness favoring high performance on standardized achievement tests. A comparison of the combined patterns of teacher directiveness and learner support revealed that the presence of low teacher directiveness and high learner support produced average grade equivalency scores which were a full year higher than those of any of the other three combined patterns. (Author/KS)