Within Canada, the examination of stratification and mobility has traditionally been related to both class and ethnicity. Previous research has not examined the theory that educational institutions may be, in part, perpetuating the vertical mosaic, because teachers assume that children from certain ethnic groups can learn more and faster than children from other ethnic groups. This document reports on research dealing mainly with the relationships among ethnicity, teachers' expectations, and the differences in educational performances of French-speaking and Yiddish-speaking students, when the effects of ability, aspirations, and a number of other theoretically relevant variables have been taken into consideration. A causal model incorporating both normative and cognitive expectations of teachers was used, with data limited to students in grades 9 and 10. Results show that teachers appear to base their expectations upon intellectual ability and past performance of students rather than upon ethnicity, sex, and socioeconomic status. Moreover, the data indicate that expectations affect the teachers' assigned grades to a greater degree than they affect student achievement on standardized examinations, in which ethnicity does relate to the results. Three pages of notes, three pages of references, two figures, and three tables are appended. (Author/IW)