Stress is a major risk factor in the etiology of several psychiatric diseases, such as anxiety disorders and depression. On the other hand, a growing body of evidence has demonstrated that astrocytes play a pivotal role in the normal functioning of the nervous system. Hence, understanding the effects of stress on astrocytes is crucial for a better comprehension of stress-related mental disorders. Here, we describe the evidence showing astrocyte changes induced by stress in animals and how this plasticity could operate to induce behavioral sequelae. In addition, human data linking astrocytes with psychiatric disorders related to stress are also discussed. Altogether, the data indicate that both chronic and acute stressors are capable of changing the morphology and function of astrocytes in the brain areas that are known to play a critical role in emotional processing, such as the prefrontal cortex, hippocampus, and amygdala. Furthermore, different lines of evidence suggest that astrocyte plasticity may contribute to the behavioral consequences of stress.