The main difference between a Master of Arts in Teaching (MAT) and a Master of Education (MEd) is their focus and intended audience. An MAT is ideal for professionals who already have a bachelor's degree in a subject area and want to become certified to teach in that area. An MEd, on the other hand, is more focused on education theory and research, and is often pursued by educators who want to advance in their careers or specialize in areas like curriculum development or educational administration.