Collaborative consumption refers to the sharing of products and services between individuals and businesses through online marketplaces. As identified by advocates of these new business models, peer-to-peer (p2p) marketplaces in particular rely on a foundation of trust between users, since they involve higher risks than business-to-consumer e-commerce. This bachelor thesis investigates how trust can be built between strangers in p2p marketplaces with the help of online trust systems. After an introduction to the concept of collaborative consumption, the first part examines how trust is created on the Internet, drawing from theories of trust from various disciplines and e-commerce literature. Part two analyzes how online trust systems can reduce the risk of p2p transactions on the basis of qualitative interviews with various entrepreneurs, researchers and social innovators involved in the collaborative consumption movement. Suggestions for the practical implementation of online trust systems and future research are discussed.