The purpose of this sequential mixed methods study was to examine the relationship between classroom climate and student achievement of middle school students. A purposeful sample of 428 middle school students (6th-8th grade) from a large southeastern Texas school district were administered the "Learning Environment Inventory" (LEI) to measure their perceptions of their classroom environment in terms of its cohesiveness, material environment, formality, and level of satisfaction. Data were also collected from state assessments and focus groups. Although the quantitative findings indicated that a relationship did not exist between classroom climate and student mathematics and reading achievement, the qualitative data, however, revealed that student learning is influenced by building relationships, availability and organisation of classroom resources, establishing classroom guidelines, and making the students feel safe and cared about in the classroom.