This study presents a professional development (PD) model for promoting preschool teachers' writing instruction utilizing teachers' reflective practices. Thirteen prekindergarten teachers were followed for the entire pre-K year. Teachers were assigned to intervention and comparison conditions. A reflective PD workshop was developed based on classroom observations and teachers' reflections during the Fall semester. Intervention group teachers completed a reflective PD workshop, and a reflective teacher-researcher meeting in the Spring semester. By the end of the pre-K year, classroom observations suggested that the intervention group teachers provided a significantly higher quality of literacy and writing instruction than comparison group teachers. Intervention group teachers also implemented new teaching practices with high fidelity. Findings demonstrate the merit and necessity of utilizing reflective practices during in-service teachers' training. The description of the reflective PD model and teachers' initial teaching practices are also discussed in this article.