As with the choice of a Montessori school for children, an adult must also exercise wisdom in choosing a teacher training course. Anyone can legally use the name "Montessori" in describing their teacher training organization. One must be sure the certification earned is recognized by the school where one desires to teach.
The two major organizations offering Montessori training in the United States are the Association Montessori Internationale (AMI, with a U.S. branch office called AMI-USA) and the American Montessori Society (AMS). Most training centers require a bachelor’s degree for admission. Training ranges from 200 to 600 pre-service contact hours and covers principles of child development and Montessori philosophy as well as specific uses of the Montessori classroom materials. Montessori training centers can be found across North America and around the world.
There are other courses which can help one better understand Montessori theory or which can train adults to work in certain schools. It is important to balance the amount o time and money one can spend with the teaching opportunities desired.