<p>Prior research has linked parental factors such as parent psychopathology, family functioning, parenting style, and parental practices to child anxiety and depression. Parents are often involved in interventions for these disorders. However, previous research suggests that this does not always add to the effect of child treatment alone. Furthermore, little research report changes in known parental risk and protective factors. As part of the ECHO-trial, we examined two delivery formats of parental involvement in the <i>Emotion</i> intervention, an indicated school-based cognitive behavioral therapy (CBT) program to prevent child anxiety and depression. Parents received either five parent group sessions or a brochure, while their children attended group sessions. Parents&#xa0;(<i>N</i> = 1028) completed our online survey at baseline, post-intervention, and/or 12-month follow-up. On average, parents showed small improvements in anxiety and depression symptoms and parental practices&#xa0;over time. There was no difference in parental factors between parents in the group sessions and the brochure condition.</p><p>The trial was preregistered at <a href="https://www.clinicaltrials.gov/">https://www.clinicaltrials.gov/</a> (NCT04263558), in February 2020.</p>