This paper aims to examine the factors that influence the willingness to adopt mobile payments and the behavior intention to adopt among Thailand and Sweden's older adults. The developed Unified Theory of Acceptance and Use of Technology model was adopted as a conceptual framework and a measurement for this study. The five factors include performance expectancy, effort expectancy, social influence, facilitating conditions, and perceived risk are the independent variables plus the behavior intention to adopt mobile payments as a dependent variable. A quantitative analysis approach has been chosen to obtain data that can be statistically analyzed and compared. A total of 303 of the target respondents in Thailand and Sweden were collected through self-administered questionnaire surveys and analyzed with ADANCO with the partial least square method. The empirical results revealed a significant relationship between most factors with effort expectancy as the only insignificant determinant. For instance, the findings show that social influence has a substantial positive impact on the Thais and a significant impact on Sweden's willingness to adopt mobile payments. Further, perceived risk was found to negatively impact the adoption of mobile payment services in both countries. Still, the fear of losing money was significantly less in Sweden than in Thailand.