<p>The present preregistered study aimed to evaluate the effectiveness of two types of group interventions delivered online in counteracting parental burnout and its accompanying problems: depressive symptoms, child abuse and neglect, perfectionism, dissatisfaction of psychological needs, and difficulties with parental reflective functioning. The randomized controlled trial involved 118 mothers (<i>M</i>_age = 36.07, <i>SD</i> = 5.10). The mothers were randomized to three groups: two intervention conditions lasting eight weeks each (Mindfulness-Based Cognitive Therapy and Parenting in Balance) and a control group (waiting list). The studied variables were measured before the intervention, 24–48&#xa0;h after the intervention, three months after the intervention, and six months after the intervention. The results revealed that both interventions effectively and to a similar degree reduced parental burnout in mothers, even six months after the intervention. Moreover, parental burnout declined further after the interventions suggesting that the interventions tested allowed mothers to develop the competencies they used to cope autonomously. Concerning other characteristics, some differences in effectiveness occurred between the two types of interventions. The present study is the first evidence of the effectiveness of online group support in counteracting parental burnout in mothers.</p>