This study investigates the extent to which social connectedness may mediate the link between ontological security and subjectively measured well-being of Australia’s baby boomers. The results indicate that, on average, for Australia’s baby boomers, a relative lack of ontological security is associated with lower levels of well-being and social connectedness. Further, social connectedness is linked to higher levels of well-being. These findings hold, whether or not other things are held constant. In addition, there is some evidence to suggest that social connectedness partially mediates the link between ontological security and well-being. Further investigation reveals that the nature of the link between ontological security and well-being may depend on a resident’s age. Most strikingly, social connectedness is found to consistently attenuate and completely mediate this age-specific negative link between a relative absence of ontological security and well-being.