This study examined the nature and impact of two aspects of classroom learning (interpersonal teacher behavior and classroom climate) on the affective and cognitive outcomes of elementary mathematics students in Singapore. A secondary purpose was to explore gender differences in students' achievement, attitudes, and perceptions of the classroom environment. A random sample of 1,512 boys and girls from government elementary schools was used. For the analysis of environment-outcome associations, simple, multiple, and canonical correlation analyses and multilevel (hierarchical linear model) analyses were conducted using two units of analysis, the individual student and the class mean. For the analysis of gender differences, multivariate analyses of variance (MANOVA) for repeated measures were performed for the two outcome measures and the classroom environment scales. Overall the different methods of analysis yielded consistent associations between classroom environment and student outcomes. Gender differences were detected in mathematics achievement in favor of boys, but girls generally viewed their classroom environment more favorably than the boys did. (Author)