Ethnicity has been shown to be an important factor in the development of body image, which in turn has consequences for our health and well-being. Several nonwestern cultures traditionally have a heavier body ideal than the current western thin body ideal, although there is now evidence of a globalization of the current western slim and fit body ideal. Data from Longitudinal Young in Oslo (LUNO) was used to explore whether there is a difference in body image between ethnic groups, if these can be attributed to culture, and the relationship between indicators of acculturation and body image. Participants were 2328 9th graders in Oslo, a quarter of which were nonwestern. Several ethnic differences in body image emerged for girls that may be attributed to culture. Specifically, nonwestern girls were found to be less invested in their appearance and less influenced by media ideals than western girls. Girls with stronger Norwegian identity were more satisfied with their appearance. Norwegian born students were more invested in their appearance and more influenced by media body ideals. And Muslim girls were found to be less invested in their appearance and less influenced by media ideals than all other girls. There were no significant ethnicity-based differences for boys. These differences were small but significant, and support earlier findings of cultural differences in body ideals. The results were inconclusive in finding changes in body image due to acculturation. Some results are consistent with a globalization of the current western body ideal.