Variability in ecological risk perceptions was investigated by surveying members of four stakeholder groups commonly involved in environmental policy debates. Fifty-six individuals from government, industry, environmental, and general-public groups completed a risk-perception survey in which they evaluated 34 environmental hazards on 17 attributes and also evaluated the riskiness and acceptability of each hazard. In addition, participants reported their environmental beliefs and norms using Dunlap et al.'s revised New Ecological Paradigm Scale and modified versions of Schwartz's Awareness of Consequences and Personal Norms Scales. Group membership was predictive of participants' scores on the belief and norm scales. Factor analysis of attribute ratings (averaged across participants) revealed the anticipated three oblique factors: ecological impacts, scientific understanding, and aesthetic impacts. Factor patterns were very similar for the four stakeholder groups. Factors from the aggregate analysis were predictive of individuals' riskiness judgments, but these relationships were moderated by participants' group membership, beliefs, and norms. Compared to members of other groups, members of the general public placed less emphasis on ecological impacts and more emphasis on the other two factors when judging the ecological riskiness of hazards. To our knowledge, these results represent the first formal tests of interactions between hazard characteristics and participant characteristics in determining riskiness judgments, and illustrate how traditional psychometric analyses can be successfully coupled with individual-difference measures to improve the understanding of risk perception.