Online advertising is an essential element of the todays marketing communications. Throughout the different generations of the world there have been significant trends and tremendous research has been put into this area especially where Generation Z is concerned. This research evaluates the different factors that affect the buying decision of individuals of Generation Z and a comparative analysis is also performed with the individuals of Generation X and Y too. The research explores how online reviews, sponsored user generated content and brand image has an impact on the buying decisions of Generation Z and how they act differently towards it when compared to the older generations. Furthermore interaction of gender and buying decisions of Generation Z is also analysed. A total of 100 responses was completed from individuals across different generations collected through an online survey. Data collected explores the different aspects of online advertisements and the factors as per literature which covered areas of online advertisements arena, eWOM, purchase decisions and intentions, social media background and the role of online communities, online reviews and brand image on buying behaviour of Generation Z specifically. This knowledge greatly helps the marketer through varied array of practical implications in today’s world. From the findings it can be concluded that Generation Z indeed have inclinations though which they decide upon buying a product that other generations might or might not be affected giving rise to different trends of online purchasing and behaviour.