Background There is a signifcant gap between the prevalence of child and adolescent mental illness in Mexico and access to mental health services, especially those that are evidence-based. School-based interventions can signifcantly narrow this gap. Objective The study evaluated the efectiveness of the interventions Dejando Huellitas en tu Vida (Leaving Traces on Your Life [Huellitas]) and Criando con Amor, Promoviendo Armonía y Superación en México (Raising Children with Love, Promoting Harmony and Self-Improvement [CAPAS-Mx]). Methods Participants were 215 caregivers (Mage=38.4 years, SD=8.9, 82.9% women) and 202 children (Mage=8.6 years, SD=1.3, 44.06% girls) from four public schools randomly assigned to four experimental conditions (Huellitas, CAPAS-Mx, Huellitas-CAPAS-Mx, and Control) with pre-test and post-test assessments. Results Caregivers in the multicomponent condition reported signifcantly lower scores in child externalizing problems and higher scores in discipline, skills encouragement, social adaptation, emotional control and prosocial behavior than caregivers in the control group. There were also improvements in parents’ use of efective discipline and skills encouragement in the CAPAS-Mx group over the control group. Among the children, only those in the Huellitas condition showed a decrease in mediation. Conclusions Findings support the implementation of the multicomponent intervention in public school settings. Registry ID ISRCTN11345846, at https://www.isrctn.com/