The purpose of this study was to determine the relationship between professional learning community (PLC) characteristics and levels of trust, and their impact on student academic achievement in fifth and eighth grade mathematics, based on Georgia's state academic test. This research was designed to answer the following questions: is student academic achievement impacted by perceived levels of PLCs? Is trust a determining factor in the implementation level of PLCs? Do schools that exhibit high levels of trust, and characteristics of PLCs, have higher student academic achievement scores? Is there a difference between middle and elementary schools in regards to student achievement when examining the effects of PLC implementation and level of trust? Data were collected from 59 elementary and middle schools in Georgia using Hord's (1996) School Professional Staff as a Learning Community Questionnaire (SPSLCQ) and the Omnibus T-Scale (Hoy & Tschannen-Moran, 2003). Student achievement data were obtained from the Georgia Department of Education website. Data were analyzed through correlations, stepwise backward regressions, and independent t-tests using SPSS 20.0. Results indicated that there is a strong relationship between trust and professional learning communities and that higher levels of trust in clients (students and parents) have an impact on student academic achievement. Results also indicated in this study that professional learning communities were not a significant predictor of student academic achievement; however they may have an indirect impact on achievement through the relationship with trust. [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/en-US/products/dissertations/individuals.shtml.]