The rapid growth of digital payment systems has significantly transformed India's financial ecosystem, with the Unified Payments Interface (UPI) emerging as one of the world's most successful real-time payment platforms. Developed by the National Payments Corporation of India (NPCI), UPI has simplified financial transactions by enabling instant fund transfers through mobile devices. This study examines the adoption of UPI and its influence on consumer payment behaviour in India. The paper explores the factors driving UPI adoption, including convenience, ease of use, security, accessibility, government initiatives, and technological advancements. It also investigates how digital payments have changed consumer spending patterns, reduced dependence on cash, and promoted financial inclusion. The study is based on secondary data collected from research articles, reports published by the Reserve Bank of India (RBI), NPCI, government publications, and peer-reviewed journals. The findings suggest that UPI has become an integral part of consumers' daily financial activities due to its speed, interoperability, and user-friendly interface. However, concerns related to cybersecurity, digital literacy, internet connectivity, and fraud continue to affect consumer confidence. The study concludes that strengthening digital infrastructure, improving financial awareness, and enhancing cybersecurity measures are essential for sustaining long-term growth in digital payments in India.