The growth of e-commerce has had a considerable impact on the consumer purchasing behaviour particularly in Coimbatore City where internet purchases are being embraced. It analyses the psychological aspects that motivate unplanned online purchase behaviour, including the fear of missing out (FOMO), emotions, impulsiveness, scarcity, urgency and digital marketing tactics like flash sales and personalized recommendations. The structured questionnaire was used to gather primary data in the form of 100 online consumers, which was supported by secondary sources. Such statistical tools as percentage analysis, mean analysis, chi-square and ANOVA were used. The results demonstrate that there is a close relationship between triggers of psychological responses and impulsive online purchases, thus the necessity of ethical and responsible digital marketing.

Dr.Poornima B, Ms.Santhiya Priyadarshini M, "Psychological Factors Driving Unplanned Online Purchase Behaviour Among Consumers in Coimbatore City" International Journal of Advanced Multidisciplinary Research and Educational Development, V2(1): Page(1293-1298) Jan-Feb 2026. ISSN: 3107-6513. www.ijamred.com. Published by Scientific and Academic Research Publishing.