The term “Montessori” is not copyrighted or trademarked, so its use does not guarantee any level of teacher training, accreditation, or authenticity. Several organizations offer Montessori accreditation.
AMI-USA: In the United States, AMI-USA grants AMI Recognition status to schools based on the training of their teachers and their adherence to AMI pedagogical standards. Requirements for Recognition include:
staffing: One AMI trained teacher (at the appropriate level) and one assistant (with some exceptions) per classroom.
materials: A complete set of Montessori materials from an approved manufacturer.
class size and age range: Class sizes and age ranges detailed at AMI-USA.
work periods: Two to three hour uninterrupted work periods, depending on the age group, are required.
AMI-USA also grants Affiliated and Associated status, with somewhat looser requirements, which give schools a three-year period in which to achieve Recognition. The Recognition process consists of a written application and an on-site visit from an AMI consultant. About 200 schools are AMI Recognized.
AMS: AMS offers membership to schools at various levels. Full members must have one trained teacher, with credentials from AMS, AMI, NCME, or any teacher training program accredited by MACTE, at the appropriate level for each classroom. Associate level members must have some, but not all, trained teachers, and Initiate level members have a three-year period in which to achieve Associate or Full membership. All members must subscribe to the AMS Code of Ethics. Membership currently includes 1200 schools.
In addition, AMS member schools may apply for AMS Accreditation, a one to two year self-study and onsite peer review process. About 120 AMS member schools are AMS Accredited.