My thesis ‘The Impact of Social Media Advertising on Consumer Behavior: A Comparative Study of Facebook, Instagram and X (formerly Twitter)’ examines how social media changes consumer behavior. The study used a primarily quantitative approach to survey 100 participants to determine how advertising on these platforms affects consumer perceptions, preferences and purchase intentions. The research was framed within the Theory of Planned Behavior and Social Influence Theory to fill literature gaps. It investigated how different social media platforms affect consumer behavior and how their unique characteristics affect advertising. Interesting differences were found across platforms.