The effects of school inclusion programs on male and female nondisabled students' stereotypes and attitudes toward people with Down syndrome were studied. Nondisabled students (11–15 years of age) from schools with and without inclusion programs reported positive and negative attitudes toward people with Down syndrome. As hypothesized, girls and students attending schools with inclusion programs showed more favorable attitudes toward people with Down syndrome than did boys and students attending schools without inclusion programs, respectively. Interaction effects of school system and sex of participant suggest that boys' attitudes, in particular, benefit from inclusive schooling. The study provides evidence for the effectiveness of inclusion programs in ameliorating prejudice and intergroup anxiety; and in promoting positive attitudes, affect, and trust.