Science achievement and attitudes were assessed for a series of students in Grades 3–12 representing the four major ethnic groups in Hawai'i (USA). It was found that more differences were accounted for by ethnicity and even grade than by gender; in addition, there was little interaction between ethnicity and gender. With respect to ethnicity, Caucasian and Japanese-American students outscored Hawaiians and Filipino Americans at all grade levels. Caucasians also expressed the most positive attitudes toward science and Japanese expressed the most positive perceptions of scientists; Hawaiians generally expressed the least positive perceptions. Younger students generally expressed more positive attitudes toward science but less positive perceptions of scientists compared to older students. Caucasians expressed the most positive perceptions of their own science ability and achievement. With respect to gender, there were no consistent differences in science achievement and very few in science attitudes and perceptions. The major differences were that males reported more experiences with physical science activities and also expressed a more male-stereotyped view of science than females, with some variation by ethnicity and grade. There were differences in enrollment in advanced science and mathematics classes in that females were more likely than males to enroll in many, but for both genders the major reason was college admission: Japanese students were most likely and Hawaiians least likely to indicate science interest as a reason. Findings are discussed within the context of cultural ecology and feminist social theory. © 1996 John Wiley & Sons, Inc.