The Effect of Social Media Marketing on Consumer Purchase Behaviour: A Study of Young Adults in Lagos State

This study examines the effect of social media marketing on consumer purchase behaviour among young adults in Lagos State, South West Nigeria. The rapid proliferation of digital platforms such as Instagram, TikTok, and X (formerly Twitter) has fundamentally altered how businesses communicate with potential customers, particularly among the 18 to 35 age bracket. Despite widespread adoption of social media by Nigerian brands, empirical evidence on its actual influence on purchase decisions within Lagos remains fragmented. This study adopts a descriptive survey design, drawing on a sample of 320 respondents selected through stratified random sampling across three local government areas in Lagos. A structured questionnaire validated by experts constitutes the primary data collection instrument. Data analysis employs frequency tables, percentages, and Pearson correlation. Preliminary observations suggest that sponsored content, influencer endorsements, and user-generated reviews significantly shape consumer attitudes and intentions. The study also investigates the moderating role of brand trust in this relationship. Findings are expected to assist marketing managers in designing more targeted and cost-effective digital campaigns suited to the Nigerian urban consumer. The research contributes to the growing body of literature on digital marketing in sub-Saharan Africa and provides actionable recommendations for small and medium enterprises seeking to leverage social media for competitive advantage in saturated retail markets. Keywords: social media marketing, consumer behaviour, purchase intention, Lagos, digital advertising