This study examines how public perception of threat and efficacy (on self and others) influence their tendency to take preventive action against the Zika virus by surveying 1,152 U.S. adults in Texas and Florida. Findings show that individuals were likely to take protective actions when they: (1) saw a high risk of the disease (high threat) and were confident about their ability to reduce the danger (high efficacy); and (2) perceived others as having a high risk (high threat), but lacked the ability to reduce the danger (low efficacy). Further, the study discusses practical implications for the design of public health campaigns.