Adoption of UPI and Mobile Wallets: A Study on Changing Payment Behaviour Among Millennials

India’s payment ecosystem has changed as a result of the quick digitization of financial transactions. Mobile wallets like Google Pay, PhonePe, and Paytm, as well as the Unified Payments Interface (UPI), have been increasingly popular, especially among millennials. With an emphasis on adoption-influencing elements including convenience, security, and perceived utility, this study attempts to examine the behavioral change from cash-based to digital payments. To collect primary data on usage frequency, preferred platforms, and trust levels, a structured questionnaire was distributed to 100 urban millennial respondents. To interpret trends, the study uses Excel for descriptive and correlation analysis. The results show that while security concerns continue to be a considerable barrier, convenience and cashback rewards greatly boost adoption. According to the study’s findings, millennials’ strong adoption of UPI and wallets is a result of their digital awareness and lifestyle alignment. In order to improve customer retention and trust in digital payment platforms, the paper offers management insights for banks and fintech companies.