Over the past decade, research linking sleep and social relationships has burgeoned. Researchers across the globe are trying to understand whether the quality and quantity of our social relationships matter for sleep, and vice versa. We conducted a systematic review of the literature, identifying over 200 relevant articles examining sleep and social relationships in healthy populations. Here, we summarize our findings by reviewing 1) links between sleep and broad social ties across the lifespan, and 2) links between sleep and specific social relationships identified in the literature search, including romantic relationships, family relationships, and work relationships. Taken together, the literature provides evidence that the quality and presence of social relationships, especially our closest relationships, play a role in how we sleep. Likewise, sleep appears to influence our social bonds. However, the majority of work is correlational, limiting conclusions about the directionality of these effects. We conclude by synthesizing the findings, considering the limitations of the present literature, and identifying key future directions for this emerging area of research.