The COVID-19 pandemic disrupted all areas of society. The socio-emotional effects of isolation, financial instability, and educational and employment uncertainty are expected to impact the mental health of parents and children, a phenomenon not yet explored in the Puerto Rican context. To investigate the impact of COVID-19 on families in Puerto Rico, we used a correlational and cross-sectional research design that addressed the following aspects: (a) Adverse experiences (EA) related to the pandemic reported by parents; (b) Parental stress; (c) Parental psychopathology; (d) Children's mental health. Our hypothesis stated that AEs exert direct and indirect effects on children's mental health, mediated by mental health and parental stress. One hundred and thirty-five parents with children between 4 and 18 years old completed an anonymous online survey between March and May 2022. The results reveal that AEDs linked to COVID-19 have significant direct and indirect effects on children's mental health, mediated by parental stress and psychopathology. Moderate to large effect sizes were observed in associations between childhood mental health and AD, mediated by parental stress and psychopathology. Children's mental health symptoms intensify as parental stress and psychopathology increase in the context of COVID-19 related ADs.