<p>Children often display less positive attitudes toward children whose behavior differs from gender norms, which is concerning given the importance of peer relations in fostering positive mental health among gender-nonconforming youth. Prior research on children’s perceptions of gender-nonconforming peers commonly employed peer appraisal measures focused on narrow domains (e.g., friendship preference), whereas perceptions of peers’ traits (e.g., smart, nice) provide a broader measure of attitudes. The present study explores the relationship between children’s level of gender stereotyping and trait perceptions of hypothetical gender-nonconforming peers. In a sample (<i>N</i> = 186) of 8- to 11-year-old Canadian children, greater gender stereotyping was associated with less positive trait perceptions of gender-nonconforming hypothetical peers. Thus, 8- to 11-year-olds who endorse gender stereotypes are more likely to broadly perceive gender-nonconforming peers less positively. Future intervention work may target gender stereotypes as a means to improve children’s attitudes toward peer gender nonconformity.</p>