The purpose of this study is to research the impact of social media (Twitter, Facebook and Instagram) on consumer behaviour in Nigeria. The objectives of the study are: (i) determine the impact of social media networks on (Facebook, Twitter and Instagram) on consumer purchase decision in Nigeria; (ii) ascertain the impact of Twitter, Facebook and Instagram on the shopping decisions of young consumer segment in Nigeria; (iii) examine the impact of Twitter, Facebook and Instagram on the shopping decisions of older consumer segment in Nigeria. This research adopted the Model of Consumer Behaviour for its theoretical analysis and a quantitative-based cross-sectional survey design for its methodology. Using convenience sampling method, the study selected 128 participants through an Online Google Form questionnaire. Data collected were analysed through Correlation Coefficient and Multiple Linear Regression analysis. Findings showed that while most of the participants were all more likely to buy and/or sell on social media than on any other channel or physical place, when tested, the first hypothesis that examined the impact of social media networks (Twitter, Facebook and Instagram) on consumer purchase decision in Nigeria was rejected because it had no significant association with participants’ consumer purchasing decisions in Nigeria. This study recommends that owners of social media networks pay more attention to the security of their platforms if they want to benefit from the gains of ecommerce. Particularly, owners of Instagram, Twitter and WhatsApp, which are the most used social media networks for e-commerce by participants. Therefore, they should invest more in building the infrastructure and security of their networks in order to gain the trust and confidence of their customers.