Social media marketing has brought new challenges for marketers, particularly in gaining consumer trust, which is crucial for establishing and maintaining consumer relationships. TikTok, a social media platform, has experienced significant user growth and is now one of the most popular platforms among young people. With the rise of TikTok, new marketing dynamics have emerged, including user-generated content (UGC), where consumers independently create and share their own content without direct commercial incentives. Previous research indicates that UGC tends to generate higher levels of trust compared to traditional commercial content. The purpose of this thesis is to investigate the key concepts that influence consumer trust in UGC on TikTok, specifically focusing on virality, awareness, and source credibility, including authenticity, expertise, and trustworthiness. A qualitative approach was used and semi-structured interviews with Generation Z consumers were used to gather insights. The results showed although virality and awareness are associated with higher engagement levels, they do not necessarily promote trust. Instead, the concepts related to source credibility, particularly authenticity, expertise, and trustworthiness, were more frequently highlighted as building trust. Consumers tend to trust UGC which comes from sources perceived as authentic, knowledgeable, and trustworthy.