Background <p>Loneliness is associated with poor health and impaired sleep quality with evidence suggesting a bidirectional relationship between sleep and loneliness, where loneliness may disrupt sleep, and likewise time awake at night may enhance feelings of loneliness.</p> Methods <p>In this study, we investigated the role of brooding rumination and anxiety sensitivity in moderating (amplifying) the association between loneliness and sleep quality and duration. We examined these associations in a sample of 81 college-aged adults, a population often characterized by higher rates of both loneliness and sleep disruption.</p> Results <p>Consistent with a previous study, we found that self-reported loneliness was associated with poor sleep quality but not sleep duration. As hypothesized, we found that this relationship was moderated by level of brooding rumination, with associations between loneliness and impaired sleep quality evident only for individuals with higher levels of brooding. Levels of depression did not account for these findings. We could not confirm a similar role for anxiety sensitivity in amplifying the association between loneliness and sleep disruption.</p> Conclusion <p>Brooding rumination is a modifiable treatment target; replication of these findings in a longitudinal study offers the ability to examine potential feed-forward relationships among variables, and to help confirm the potential relevance of targeting brooding rumination to benefit sleep quality in populations with elevated loneliness.</p>