Americans of Japanese ancestry rank higher than any other physically identifiable subgroup on positive attributes and lowest on negative ones. The thesis of this paper is that their success depends more on the value orientations that differentiate the two groups than upon those held in common. Data were obtained from a survey of 2200 pupils enrolled in grades six, nine, and twelve in 23 racially-mixed Los Angeles schools. Comparison of Japanese-American and Anglo samples on value orientation variables support the hypothesis that the comparatively high achievement of Japanese-Americans is related more to traditional Japanese cultural values than to acquired American values. While the two groups are similar in appreciation of the value of education and the importance of peers, the Japanese-Americans are more expressive toward school, have less belief in individual action, and have higher occupational aspirations. Japanese-Americans appear to be less acculturated to the values of the American middle class than generally believed, and explanations which rely on theories of acculturation do not adequately account for their success in American society. (Author/CJ)