In this study, a questionnaire was designed to assess Montessori teachers' reported likelihood of intervention in some 25 common situations in Montessori classrooms for 3-6 year olds, as well as to obtain limited background information on the teachers. Subjects were 422 Montessori teachers including 30 from Trinidad (where the questionnaire was first designed and field tested), 9 from Haiti, 362 from the United States, and 21 from Canada. Care was taken to ensure that each of the major Montessori teacher training organizations was represented in the sample. The primary research question to be answered was whether or not Montessori teachers say that they intervene in children's use of materials that require seriation or classification. Additional questions examined reported likelihood of intervention in fantasy play, math errors, language errors, general errors of fact, disruption, and dangerous activities. Findings showed that in the area of seriation and classification activities, Montessori teachers are quite consistent in reporting that they are not likely to intervene, while in the area of math and language, teachers are more likely to respond to errors. In the area of fantasy play results show that Montessori teachers are much more variable in their responses. While this could indicate that Montessori teachers are working to individualize their responses to each child in each situation, in fact it probably means that many teachers are uncertain how to respond to fantasy play in the Montessori classroom. (SH)