Understanding the development of public opinion about emerging technologies, when the scope of that emergence is still speculative, poses particular challenges. Opinions and beliefs may be drawn from conflicting experts in multiple fields, media portrayals with varying biases, and fictional narratives that portray diverse possible futures. This article draws on research in cognitive and social psychology to discuss how fiction in particular may influence beliefs about emerging technologies such as nanotechnology and biotechnology. Fiction can affect beliefs about the developments that are most likely, the relative weight of possible risks and benefits, and the desirability of potential technology-related outcomes. These beliefs, in turn, influence public support of regulation and funding, sometimes in ways that have little to do with the actual issues immediately at hand.