User-generated content is the backbone of any social networking site (SNS) and an important pillar of many business models online. While there is a growing body of research on self-disclosure on SNSs, existing insights remain scattered. To fill this gap, we undertake a systematic literature review by examining 50 studies to identify the factors behind self-disclosure on SNSs. We find that social exchange theory and its extension ‘privacy calculus’ represent a dominant theoretical perspective. Hence, we focus on perceived benefits and costs, as well as cost-mitigating factors as main areas of our investigation. Since personality traits are commonly controlled for or studied within the context of SNS disclosure, we additionally include an exploration of this factor group into our review.