Novel foods have been the object of intense public debate in recent years. Despite widespread efforts to communicate the outcomes of risk assessments to consumers, public confidence in risk management has been low. Social scientists have identified various reasons for this, including a disagreement between technical experts and consumers over the nature of the hazards on which risk assessments should focus. The aim of this study was to identify and compare the ways in which experts and consumers understand the benefits and risks associated with a genetically modified example crop. Two qualitative studies were conducted. In Study 1, mental models were elicited from 24 experts by means of a three-wave Delphi procedure. In Study 2, mental models were elicited from 25 consumers by means of in-depth interviews. As expected, the expert mental models were focused on the types of hazards that can realistically be addressed under current regulatory frameworks, whereas the consumers were often more concerned about issues outside the scope of current legislation. Moreover, the experts tended to define risk and benefit in terms of detailed chains of cause-effect relationships between variables for which clear definitions and measurement rules exist. The concepts the consumers used when reasoning about biological processes were very abstract, suggesting that the participants had, at most, a holistic understanding. In line with this, issues of uncertainty played a prominent role for the consumers.