The purpose of this study was to explore the use of Professional Learning Communities (PLCs) in preservice teacher education as a tool for learning about differentiation within writing instruction. Using online dialogue journals, preservice teachers communicated with elementary students about a shared text and met in ongoing PLC groups to examine students' work and discuss articles related to writing instruction. In end-of-course reflections, preservice teachers reported new understandings of how to guide individual students toward reasonable writing goals, as well as increased confidence in their ability to teach writing and to differentiate instruction as a result of participating in the PLCs. In particular, preservice teachers learned to build upon students' strengths in an effort to facilitate growth over time.