Global efforts to reduce the spread of COVID-19 have focused on promoting adoption of behaviors such as regular hand washing and avoiding touching the face to avoid infection transmission. This study aimed to (1) evaluate the efficacy of a novel imagery-based intervention in promoting the avoidance of touching one’s face with unwashed hands; and (2) evaluate the effect of the intervention on social cognition outcomes, compared to a control, after one week. The study adopted a pre-registered randomized controlled design. Study 1 tested imagerybased intervention effects in a sample of Australian residents (N = 254, 52.0% men). Participants received the intervention or education-only comparison group condition stimuli online and completed measures before and 1-week after the intervention. Study 2 was a conceptual replication identical in design to Study 1, but also included a no-intervention control condition, in a sample of US residents (N = 245, 56.7% men). Mixed-model ANOVAs revealed a significant increase in avoidance of touching the face with unwashed hands from pre-intervention to follow-up irrespective of intervention condition in both studies, but no significant condition effects. Exploratory analyses revealed significant effects of the theory-based intervention on behavior at follow-up in individuals with low preintervention risk perceptions in Study 2. Both studies indicated high adoption of avoiding touching one’s face with unwashed hands, with behavioral engagement increasing over time independent of the intervention. Further pre-registered interventions are recommended to test the moderating effect of risk perception, and the efficacy of the present intervention during a regular influenza season.