Objective: To describe the probability of appropriate hand hygiene behaviors among outpatients and visitors at a primary care unit before and after installation of additionally strategically placed hand rub dispensers and empirically-designed behavioral nudges.  Material and Methods: We conducted a quasi-experimental study at a suburban primary care unit in southern Thailand. The intervention consisted of included installation of hand rub dispensers and attachment of behavioral nudges. We designed the behavioral nudges using qualitative data from a focus-group discussion with local residents, who identified disgust and normative expectations from children as the main behavioral drivers for following appropriate hand hygiene behaviors. We then conducted surreptitious observations of hand hygiene behaviors among outpatients and visitors before intervention delivery during Wave 1 and Wave 2 of the pandemic (Phase 1 and Phase 2, respectively), after installation of the hand gel dispensers alone (Phase 3), and after attaching behavioral nudge signs to the dispensers (Phase 4).  Results: The probability of appropriate hand hygiene behavior increased from 0.6 percent in Phase 1 to 13.5 percent in Phase 4. However, the increase was statistically significant only from Phase 2 to Phase 3 in the zones where the dispensers were located (adjusted odds ratio 10.58; 95% confidence interval 1.95, 57.24). Conclusion: The probability of appropriate hand hygiene behavior after installation of the dispensers was significantly higher than at pre-intervention, but the difference in appropriate hand hygiene before and after attachment of the nudges to the dispensers was not statistically significant. The study findings could nonetheless contribute empirical evidence on observed changes in hand hygiene behaviors in a primary care setting.