Nearly 100 Mexican American children and adolescents in grades 2-12 were interviewed in central Texas to determine their understanding of ethnicity and their attitudes toward their own ethnicity. Their responses were interpreted in relation to a developmental model with five stages or "perspectives" in reasoning about ethnicity. The first level, Level 0 (ages up to 6-7 years), involves primarily a physical perspective on ethnicity, in which children use skin color or facial features to make racial/ethnic classifications. Children at this level tend to base ethnic pride in either a generalized pride in themselves or a pride specific to their physical characteristics. Level 1 (ages 6-10) involves literal conceptions of ethnicity--awareness of nonobservable aspects of ethnicity such as ancestry, cultural heritage, and language. At Level 2 (ages 8-12), children become aware of subtle social aspects of ethnicity such as social class status and ethnic bias. Level 3 (adolescence to early adulthood) involves a group perspective on ethnicity, in which youth can generalize across individuals and discrete experiences. Level 4 involves a multicultural perspective on ethnicity. Levels 0-3 are illustrated by subjects' responses to why they like being Mexican American and why someone would not like being Mexican American. An appendix categorizes children's and high school students' responses by various themes and compares them to similar responses from African American children. (SV)