Sociability- the tendency to engage in social interactions- and sleep are widely conserved phenomena crucial to all organisms. Impairments in both these processes are associated with negative outcomes such as severe cognitive decline and early mortality. The intimate connection of sleep and sociability is deeply evolutionary conserved. In species as distant as humans, Drosophila and mice, sleep impairments affect sociability and vice versa indicating a fundamental and ancient functional link. However, we have no knowledge of the mechanisms underlying sociability’s interplay with sleep and its resultant effect on cognitive function. This prevents us from understanding how they became connected to one another and why they have such a major impact on health. To shine light on this fundamental but poorly understood connection, I propose to investigate whether genes influencing sociability influence sleep and subsequently explore the neural circuits underlying this link. For this, I will use mice for their homology in brain organization to humans and Drosophila for their genetic tool-set to investigate if sociability genes influence sleep quality. This research will provide a platform to investigate the fundamental question of why sleep and sociability have co-evolved and has the potential to explain the recent realization that sociability has a severe impact on sleep, resulting in impaired cognitive function. The societal relevance is obvious in the current millennium, characterized by rapidly changing social environments, where many suffer from social impairments and sleep deficit.