Children from low-income families are at greater risk for poor social-emotional development and physical health and may be in need of intervention. This study examined the extent to which the "Positive Action" ("PA") preschool lessons improved low-income children's social-emotional competence and health behaviors. Mixed findings emerged with regard to whether the lessons facilitated growth in child outcomes. Results showed positive effects of "PA" on children's directly assessed social problem solving skills and their parent-rated social-emotional competence and health behaviors. Unexpectedly, program effects on teacher ratings of social-emotional competence were in the opposite direction. These findings provide preliminary evidence that "PA" may be effective in promoting positive social-emotional and health behavior outcomes for children, particularly when outcomes are assessed directly and by parents. [This paper was published in "Early Childhood Education Journal" v46 p141-151 2018 (EJ1165998).]