Background: Hookah tobacco is commonly used among young adults, and use is driven in part by widespread misperceptions about risks. Social media use, particularly Instagram, is prominent in this population and exposure to commercial and user-generated content promoting hookah commonly occurs. Aims: This study tested the effects of hookah tobacco risk messaging for delivery via Instagram as a strategy to offset exposure to content promoting hookah use among young adults. Method: Young adult hookah smokers were recruited online for a 2 × 3 between-subjects experiment (n = 601). Participants completed preexposure measures and were randomized to view hookah tobacco Instagram ads (commercial or user generated) with risk messages (none, risk education, or graphic risk). Stimuli were presented as a simulated Instagram feed. After viewing the stimuli, participants completed postexposure outcome measures. Results: There was a statistically significant main effect of risk message type but no significant main effect of Instagram ad type or risk message type by ad type interactions. Exposure to the graphic risk and risk education messages were associated with lower intentions to engage with hookah tobacco ads on Instagram. Graphic risk and risk education messages produced greater negative emotional response and the graphic messages increased motivation to quit compared with Instagram ads alone. Discussion: Findings provide preliminary evidence that hookah tobacco risk messages delivered via Instagram can offset the influence of content promoting the use of hookah tobacco. Conclusion: This study represents an example of risk message testing and the results suggest the messages warrant further testing via social media delivery