The purpose of this study was to investigate whether social support and stress influence maternal discipline of the six-month to three-year-old child with a developmental delay. Ninety-one mothers completed self-administered measures of support, stress, and discipline. Results of multiple regression analyses revealed that the stress and support interaction variable showed a strong trend (p< .09) in predicting restrictive discipline. The failure of the independent variables, social support and stress, to have significant main effects appeared to be due, in part, to the multicollinearity (r= -.51,p< .001) of these variables.For subsequent analyses, stress was used as a categorization variable. The total number of subjects was categorized first into two subgroups using a median split—high or low maternal stress—and into two other subgroups based on number of developmental delays. Pearson correlations indicated that social support was inversely related to restrictive discipline for high-stress mothers but not for low-stress mothers. The positive influence of social support was also found for mothers of children with three to five delays but not for mothers of children with one to two delays. A negative response style of maternal discipline was reduced when the mother felt supported.