Social isolation, exclusion, and loneliness remain powerful vulnerability factors for a wide range of negative physical and mental conditions. Although the severe consequences of unmet belonging needs are well documented, much less is known about the psychological processes that allow for the adaptive regulation of those needs. To address this gap in knowledge, my colleagues and I have proposed a belonging regulation model in which levels of social inclusion are thought to be regulated through a series of adaptive mechanisms. A key component of this model is that a perceived belonging deficit should trigger enhanced social sensitivity, which can then aid individuals in navigating their social environment resulting in smoother and more successful social interactions and greater social acceptance from others. In this talk, I will describe the belonging regulation model and also describe an on-going program of research that has yielded both correlational and experimental evidence demonstrating that individuals respond to unmet belonging needs by becoming more attuned and receptive to their social environment. The implications of this model for understanding lonely, rejection-sensitive, and socially-anxious individuals will also be discussed.