Objectives: This article reports the effects of a culturally grounded parenting intervention to strengthen positive parenting practices. Method: The intervention was designed and tested with primarily Mexican origin parents in a large urban setting of the southwestern United States using an ecodevelopmental approach. Parents (N = 393) were randomly assigned three treatment conditions: (1) a parenting and youth intervention, (2) a youth only intervention, or (3) a control group. A measurement model for positive parenting was first evaluated using confirmatory factor analysis, followed by structural equation modeling to estimate the effects of the intervention on positive parenting (i.e., baseline to follow-up). Results: As hypothesized, parents in the intervention group reported higher rates of positive parenting compared to parents in youth-only condition. Conclusion: The results are promising and add to growing evidence that interventions tailored to the cultural characteristics and environments of parents and their children can strengthen positive parenting.