The purpose of this causal comparative study was to explore the extent to which teacher perceptions of collaboration within mathematics Professional Learning Communities (PLCs) may be a differentiating factor between schools identified as "high performing" versus "low performing" based on student achievement level on the Texas mathematics assessment. The elementary schools used in this study served a majority of low socioeconomic status (SES) and Hispanic students. Prior qualitative research revealed that collaboration is an element that distinguishes high performing from low performing schools. However, a gap in the research literature is the lack of a quantitative analysis between teacher collaboration and academic achievement in Texas. For this reason, the purpose of this study was to find empirical data that may support a relationship between teacher collaboration within mathematics PLCs and mathematics achievement. The research question intended to determine to what extent was there a difference between teacher perceptions of teacher collaboration within mathematics PLCs in elementary schools identified as "high performing" versus "low performing" based on their achievement level on the Texas mathematics assessment, serving a majority of low SES and Hispanic students. The alternate hypothesis intended to find a significant relationship between the two variables. The findings of this study demonstrated a significance difference between teacher collaboration in high performing when compared with the low performing schools. The significance of the study advanced the understanding of the impact of teacher collaboration on the mathematics student achievement for Hispanic and low SES elementary students. [The dissertation citations contained here are published with the permission of ProQuest LLC. Further reproduction is prohibited without permission. Copies of dissertations may be obtained by Telephone (800) 1-800-521-0600. Web page: http://www.proquest.com.bibliotheek.ehb.be/en-US/products/dissertations/individuals.shtml.]