The rapid adoption of Unified Payments Interface (UPI) has transformed everyday payment practices and influenced the way consumers conduct routine transactions. This study examines the relationship between UPI-based digital payment usage and consumer spending behaviour among consumers in Kanyakumari District. The study is based on primary data collected from 300 respondents through a structured questionnaire. The collected data were analysed using appropriate descriptive and inferential statistical techniques. The findings reveal that UPI usage has a significant positive relationship with consumer spending behaviour and has a notable influence on spending patterns. The study also identifies differences in consumer spending behaviour across selected demographic characteristics. Overall, the findings indicate that the convenience and regular use of UPI-based digital payments are associated with changes in consumer spending behaviour. The study highlights the importance of responsible digital payment usage and consumer awareness in the growing cashless payment environment.