Family socioeconomic status (SES) and the quality of maternal behavior are among the few identified predictors of child executive functioning (EF), and they have often been found to have interactive rather than additive effects on other domains of child functioning. The purpose of this study was to explore their interactive effects in the prediction of child EF. We assessed maternal behavior at 1 year and two dimensions of child EF (Conflict EF and Impulse Control) at 3 years with 114 mother-child dyads. The analyses revealed that better child performance on Conflict EF was significantly related to higher-quality maternal behavior and to higher SES, but no interactions were found. In contrast, significant interactions were found with Impulse Control such that higher-quality maternal behavior was predictive of better performance only among children from lower-SES families. These results support the idea that distinct mechanisms may underlie the development of different dimensions of child EF.