Many factors have been associated with the development and maintenance of generalized social phobia (GSP); however, the ways in which these factors interact with one another to produce and maintain GSP remains unclear. The current paper proposes that Reinforcement Sensitivity Theory (RST) can be used to integrate a wide range of factors into a unified and theoretically-driven model of GSP. The paper begins by briefly summarizing research on genetic, temperamental, environmental, and cognitive factors associated with GSP. The next section of the paper provides an overview of RST. A model of the development and maintenance of GSP is then presented. The proposed model is unique because it: (a) integrates a wide range of factors into a unified model of GSP, (b) incorporates recent updates to RST, (c) provides a potential explanation for the differences observed among social phobia subtypes, (d) considers the role of general stressors in the development of GSP, (e) provides a biologically-based framework for understanding the cognitive biases seen in GSP, and (f) predicts the conditions under which these cognitive biases are most likely to emerge. Clinical implications and future directions for research are discussed.