Mindful parenting is linked to positive youth emotion regulation, mental health, and parent–child relationship quality. We examined bidirectional relations between adolescent mental health and mindful parenting among a diverse sample of 249 7th grade students and their female (N = 232) and male caregivers (N = 120). We conducted multiple-group cross-lagged models (grouped by adolescent sex). Female adolescents’ externalizing symptoms predicted decreased female caregiver mindful parenting six months later, but male and female adolescent externalizing behaviors were negatively associated with male caregivers’ mindful parenting one year later. Findings suggest mindful parenting capacities are vulnerable to disruption via adolescent problem behavior. Mindful parenting’s potential benefits, caveats, and need to support parent efforts to sustain mindful parenting amidst adolescents’ externalizing behaviors are discussed.