Purpose of Review <p>Social relationships exert a robust influence on psychological wellbeing as well as to structure the rhythmicity – particularly patterns of sleep and wake – of adolescents. Online social messaging (OSM; e.g., texting, Instagram, Facebook, Snapchat, etc.) represents a key impact on adolescent behaviors. We review established and emerging literature to present a new framework for understanding social messaging as a critical Social Zeitgeber and discuss the uniquely powerful role that it presents in suicidality.</p> Recent Findings <p>Unique qualities of OSM as a social zeitgeber – including social access/demands at all times – present a powerful influence on sleep and adolescent suicidality.</p> Summary <p>Research, informed by our understanding of OSM as a social zeitgeber, is needed to guide intervention development.</p>