There is a greater recognition today that sustained, high quality staff development is essential for the successful school reform. In this study levels of staff development in the US, the general trends of staff development in the US, and staff development in the school level with focus on the approaches used were examined. With systemic support of national level, state level, and school district level, school-centered staff development is emphasized. And three powerful ideas of result driven education, systems thinking, and constructivism are producing profound changes in how staff development is conceived and implemented in the US. Some of the most important of these changes are that it is changing from individual development to individual development and organizational development, and from a focus on adult needs and satisfaction to a focus on student needs and learning outcomes, and changes in on-the-job behaviors. Along with these changes, a wide range of powerful designs with the central themes of on-the-job learning, collaboration, and teamwork have been provided to the staff development leaders to help them become familiar with new ideas and strategies to improve adult learning and ultimately, improve student learning. It seems to be the time to reflect on the staff development in Korea in terms of the following aspects. What is the purpose of staff development? What are the criteria used to assess the quality of staff development programs? What are the staff development programs like depending on the levels? What are the change directions of staff development in Korea? What is the actual situation of staff development in the schools?