Awareness that an amygdala-based fear circuit plays a crucial role in mediating fear conditioning as well as anxiety symptoms is growing. The efficacy of selective serotonin reuptake inhibitors in certain anxiety disorders has been argued to reflect their ability to modulate this circuit. Whether additional neurocircuits play a differentiating role in specific anxiety disorders, such as social anxiety disorder and generalized anxiety disorder (GAD), is an ongoing subject of investigation. A review of the literature suggests that in social anxiety disorder, dopaminergically mediated striatal circuits may also be important, while in GAD, there may be abnormalities of prefrontal areas. Future work will undoubtedly clarify how genetic and environmental factors interact to fashion the neurocircuitry that mediates anxiety symptoms.