This paper reports on a series of studies that examine the multidimensional nature of achievement motivation across a number of cultural groups, the determinants of this achievement motivation, and the relationship of achievement motivation to criteria of school success, such as attendance, retention, achievement, further education, and occupational choice. These studies, conducted over 15 years, have had large samples of high school students: (1) 496 Aboriginal students; (2) 1,173 Anglo Australian students; (3) 487 Australian students of immigrant background; (4) 919 Navajo students; (5) 141 Arabic-background Australian students; (6) 198 Betsiamite (Canadian Indians) students; (7) 1,078 Anglo American students; and (8) 80 Yavapai students. A focus of the paper is an examination of the multi-method approaches used to ensure the cultural validity and reliability of the information obtained, especially the etic-emic (a model which effectively reflected key variables determined in presurveying and interviewing to be relevant to the groups being studied) considerations important in such research. Among the range of techniques used are focus group interviews, individual interviews, open-ended surveys, observations, field work, and closed survey instruments. Analysis techniques included exploratory and confirmatory factor analysis, multivariate analysis of variance, multiple regression analysis, discriminant analysis, content analysis, and non-numerical unstructured data indexing searching and theorizing (NUD.IST) analyses. Overall, findings suggest that the motivational profiles of the diverse groups participating are more similar than different, and that only a narrow range of goals and sense of self variables is important in explaining school achievement on educational criteria, and that these are similar across all the groups. (Contains 3 figures and 43 references.) (SLD)