The relationship between health psychological capital, determinants of health belief model (HBM), and individual’s adoption of preventive behaviors were studied. Participants from Pakistan (N= 323) and Malaysia (N= 343) completed an online survey. Samples from both countries were analyzed separately and compared for measurement model invariance and difference in path coefficients. Data screening, frequency analysis, and common method bias were analyzed using IBM-SPSS-25®. Partial least squares approach to SEM using SMART-PLS 3 software was adopted to analyze the measurement model, structural model, importance-performance analysis, and mediation testing. Our finding showed that model explained higher variance in preventive behavior for Pakistani samples compared to Malaysian samples. Perceived benefits followed by perceived threats were the two most important predictors of preventive behaviors in both countries. The perceived barrier was an important predictor for the Pakistani sample but had no contribution to the Malaysian sample. Health PsyCap had a direct as well as an indirect effect through perceived benefit and perceived threat (Malaysian sample only) on the outcome. Perceived seriousness and perceived susceptibility (Malaysian sample only) were related to preventive behavior through perceived threat.