Although optimistic bias has been well documented for adults, little is known about how children view their own risks vis-à-vis those of their peers. Two studies of 6th graders examined optimism and the degree of differentiation in perceived risks across diverse health, lifestyle, and environmental problems. The findings revealed perceptions of relative invulnerability and highly differentiated risk assessments. The strongest levels of optimism emerged for controllable and stigmatizing events such as illicit drugs, smoking, and AIDS. The effects of gender, assessment context, and methodological variations were minimal. Discussion focused on the implications for health-promoting interventions with school-age children, the need for developmental information about risk perception processes, and the difficulty of distinguishing realistic from biased optimism.