This study aimed to explore the effect of a mindfulness-based curriculum designed especially for preschoolers on facets of executive functions. Fifty-one preschoolers were randomly assigned to either a mindfulness and kindness curriculum (MC) or an active control dialogic reading program (DR). A battery of behavioral and neurophysiological tests was used to tap into facets of executive control (inhibition, shifting). Electroencephalography data were acquired during the attentional network task (ANT). Relative to DR, children in the MC group exhibited a reduced difference in the N200 Event related potentials (ERP) amplitudes for the congruent versus incongruent conditions during the ANT paradigm representing inhibition and shifting abilities. On the behavioral tasks, both groups improved on executive functions (EF) but on different facets; MC group showed increased inhibition and the DR group demonstrated significantly greater shifting abilities. The results highlight the sensitivity of electrophysiological data to detect subtle cognitive changes. The understanding of how mindfulness-based interventions in preschoolers affect facets of executive functions can enable further refinement and maximization of the benefits of these interventions for this age group.