One common perception is that shyness is an inherently problematic trait that lays the developmental foundation of psychosocial maladjustment. However, not all shy individuals are alike, nor are all shy individuals at risk for poor developmental outcomes. In the current chapter, we discuss heterogeneous subtypes of shyness. We place a particular emphasis on the adaptive subtype of positive shyness, which is characterized by the expression of shy behavior (e.g., gaze aversion, avoidance) in conjunction with positive affect (e.g., smiling). We review theoretical and empirical evidence suggesting that positive shyness may be an adaptive phenotype that helps the shy individual modulate arousal in social situations and helps to facilitate social approach through signaling of social interest, interpersonal trust, and appeasement, which ultimately may protect the shy individual from psychosocial maladjustment. We then propose a hypothetical model to describe the development and maintenance of adaptive and nonadaptive subtypes of shyness. We conclude with suggestions for future research that may help to further our understanding of different shyness subtypes and how they may relate to adaptive and nonadaptive outcomes across development.