The Individuals with Disabilities Education Act (IDEA; 2004) requires special educators and school districts to write individualized education programs for students with disabilities to provide them a free appropriate public education. IDEA (2004) mandates transition planning to begin for students with disabilities when a student reaches the age of 16, or before based upon need. Many special educators leave their teacher education programs with little to no preparation in transition planning which could ultimately interfere with the student’s federally mandated right to a free appropriate public education. Since teachers are not receiving adequate training in transition in their undergraduate programs, in-service professional development training is a way to help teachers gain the knowledge and skills needed to write compliant transition plans. Currently, little research exists exploring the effects of professional development on transition planning. Using a comparison group design, this study examined the effects of professional development on transition planning, and more specifically, the changes in knowledge and skills gained from the professional development training. Results of this study indicated the effectiveness of professional development on teacher knowledge of best practices in transition planning. In addition, results indicated the intervention, Stepping-Up, yielded increased scores in discriminating between compliant and noncompliant postsecondary and annual transition goals, and the creation of compliant transition plan components. Implications are discussed regarding the need for time-effective and quality professional development in transition planning and the continued need to explore the effects of professional development on actual transition planning practices.