The rise of e-commerce has led to a significant shift in consumer buying behavior, with more and more people shopping online for a variety of goods and services. However, there is a growing generation gap in terms of how Millennials and Post-Millennials shop online. This study examines the different factors that influence consumer buying behavior in online shopping among Millennials and Post-Millennials. The study found that post-Millennials are more likely to be influenced by social media and reviews, while Millennials are more likely to be influenced by brand loyalty, social responsibility, authenticity, access of information and knowledge. The study also found that Millennials are more likely to shop online for convenience, while post-Millennials are more likely to shop online for variety and personalization. The findings of this study have implications for businesses that are looking to reach Millennials and Post-Millennials through ecommerce. Businesses need to understand the different factors that influence consumer buying behavior among these two generations in order to create effective marketing campaigns. Additionally, businesses need to ensure that their websites and mobile apps are optimized for the devices that these generations use.