The rapid development of social media has changed consumer behaviour, especially that of Generation Z, who is a very active user of digital technology. This current research focuses on how social media encourages the purchase behaviour of Generation Z, especially considering the use of social media, influencer marketing, influencer credibility, product quality, and pricing. A quantitative and descriptive research approach has been adopted, and data has been collected from 461 respondents of Generation Z between the ages of 18-25 through a structured questionnaire. Stratified random sampling has been adopted for sampling. According to the results of the research, the most used social networks are Instagram (87.2%), TikTok (81.5%), and YouTube (79.8%) with daily social media use being 3.2 hours. The most frequently followed type of influencers is micro-influencers (71.2%). Authenticity is the factor that got the highest mean score (4.28) when the impact of the factors on influencer credibility was assessed. Based on regression analysis, it can be stated that recommendations by influencers have the most significant positive impact on purchase behaviour (β = 0.43, p < 0.001), followed by product quality perception (β = 0.38, p < 0.001). Price had a significant negative impact (β = −0.22, p < 0.01). This research achieves that social media and influencer marketing significantly affect Generation Z purchase decisions, along with product quality and price.