The current emphasis on job-embedded staff development for elementary school teachers has created many opportunities for teachers to be a part of a collaborative learning team. The research problem addressed in this study is that it is not known whether such collaboration impacts the instructional practices of elementary mathematics teachers. The frameworks and outcomes of collaboration in a learning community were explored. The purpose of this descriptive multicase study was to describe the collegial experiences of elementary mathematics teachers who are members of a professional learning community and the educational impact of meaningful collaboration that promotes reflection and shared knowledge. To address these research questions, the qualitative research design involved the use of multiple data sources, including teacher interviews, field notes, and review of written documents. These data sources were analyzed using single-case analysis, followed by cross-case synthesis to identify emerging and recurring themes within and across participants. To establish reliability and validity of the data, triangulation and member checks were employed. Vygotsky's theory of constructivism supports such best-practice strategies in mathematics, as teachers help students construct and explore their own ideas and connections. Results from this study suggested that collegial educators working and learning together in efforts to impact instruction in mathematics can have benefit in better equipping their students academically. In relation to positive social change, the study also provided insight into the function of collaboration in a learning community as a viable process by which to help mathematics teachers improve their instructional practices.