The study examined the effect of professional learning communities (PLC) on the achievement of students. PLC is about developing collaborative learning among colleagues to enhance the performance of an organization within a specific environment. Student achievement has defined the performance of students which can be evaluated with the help of tests. Data were gathered from SSTs (N=890) involving three districts (Sheikhupura, Kasur, and Lahore) through a multistage sampling technique. The study adopted the Professional Learning Communities Assessment (PLCA) scale to examine the PLC which was developed by Olivier et al. (2010). Student achievement scores were obtained from their respective schools based on BISE results of 10th grade. The study found that teachers strongly agreed that they were part of PLC in their institutions. The study also found a moderate and significant relationship between both PLC and student achievement (r=.71), and a 41% variance in student achievement could be explained with the help of PLC. Overall, female teachers were found better than male teachers, while urban teachers were better than urban teachers for being part of PLC. The recommendations were also added to the given study.