Mobile payment, replacing traditional methods like cash and cards, offers users convenience and accessibility, benefiting individuals, businesses, and governments. However, most research on mobile payment adoption has primarily focused on developed countries, leaving a gap in understanding the adoption factors in developing nations. This study addresses this gap by investigating the determinants of mobile payment adoption in Thailand, an emerging economy experiencing significant smartphone adoption and e-commerce growth. Through a quantitative approach and a survey of 475 Thai consumers, this research applies an extended Unified Theory of Acceptance and Use of Technology (UTAUT) model as a theoretical foundation to examine Thai consumers’ mobile payment adoption. Data analysis using SPSS 28.0 and AMOS 28.0 identifies key factors influencing Thai consumers to adopt mobile payment. By offering a comprehensive research model and considering evolving smartphone technology, this study aims to guide policymakers and stakeholders in promoting mobile payment adoption, ultimately enhancing Thailand’s economic development and tourism industry.