A semi-structured interview was used in Brazil to enquire into the "notion of model" held by a total sample of 39 science teachers who were: employed in "fundamental" (6-14 years) and "medium" (15-17 years) schools; student science teachers currently doing their practicum; and university science teachers. Seven "aspects" of their notions of a model were identified: the "nature" of a model, the "use" to which it can be put, the "entities" of which it consists, its relative "uniqueness", the "time" span over which it is used, its status in the making of "predictions", and the basis for the "accreditation" of its existence and use. "Categories of meaning" were identified for each of these aspects. The profiles of teachers' notions of "model" in terms of the aspects and categories were complex, providing no support for the notion of "Levels" in understanding. Teachers with degrees in chemistry or physics had different views about the notion of "model" to those with degrees in biology or with teacher training certificates. (Contains 4 tables and 2 notes.)