Book excerpt: The purpose of this study is to analyse the differences between upper-stream, lower-stream and mixed-ability mathematics classes in terms of student perceptions of their classroom learning environment. Both quantitative and qualitative data has been collected from students while qualitative data only was collected from pre-service teachers, practising teachers and parents. The sample for the quantitative data collection was comprised of 581 Year 9 and 10 students in 36 different classes taught by 28 different teachers in 7 schools covering 4 states of Australia. All of the schools are private schools and part of the Seventh-day Adventist school system. The questionnaire used an actual and preferred form of the 56 item version of the What is Happening in the Classroom? (WIHIC) survey along with 10 questions from the Test of Science Related Attitudes (TOSRA) modified for mathematics classrooms. For the qualitative data collection 40 interviews and 8 focus groups were conducted. Apart from comparing upper and lower-streams, other variables examined were: actual and preferred perceptions of the classroom learning environment, Year 9 with Year 10, males with females, English speakers with second language students, and attitudes with perceptions of learning environments. The most significant finding of the study was not only that lower-stream students have a more negative perception of their classroom learning environment, but that they seek less change. This negative perception is seen to be worse in Year 10 than Year 9, particularly in the areas of teacher support and task orientation. This study found a positive correlation between attitude and perceptions of classroom learning environment. This study also found a tacit acceptance of streaming as a practice by most participants in the study.