"Stress proliferation" (the tendency of stressors to engender additional stressors in other life domains) is explored in a sample of 68 parents of children identified with ASD. Regression analyses showed that parent depression was predicted by both child symptom severity and by stress proliferation and that stress proliferation partially mediated the effect of child symptom severity on parent depression. In addition, informal social support was found to reduce levels of parent stress proliferation and parent depression; however, contrary to the stress buffering hypothesis, the ameliorative effect of support on stress proliferation was shown to be greatest when reported child symptomatology was "less" (rather than more) severe. Study implications for future research and practice are discussed.