Background <p>Low positive affect (PA) is a promising treatment target for depression in mothers. PA is strongly influenced by social interactions, especially with family, suggesting the utility of dyadic interventions including children for upregulating PA. Family Promoting Positive Emotions (FPPE) is a novel eight-session, dyadic intervention for mothers with elevated depression symptoms and their children that reduces negative emotional symptoms and improves PA in youth. Although FPPE was originally designed to prevent intergenerational transmission of depression from mother to child, the dyadic structure of FPPE may also improve maternal mental health.</p> Methods <p>We extended our prior pilot study by examining the effects of FPPE (<i>n</i> = 47) compared to written information psychoeducation (<i>n</i> = 27) in intent-to-treat analyses on maternal PA, anhedonia, and depression assessed pre- and immediately post-intervention and six months later.</p> Results <p>FPPE was associated with an increase in PA and reductions in anhedonia and depression from pre- to post-intervention. No significant changes were observed in the comparison group and effects did not persist at the six-month follow-up.</p> Conclusions <p>Beyond improving youth outcomes, FPPE may also be beneficial for increasing PA and reducing negative emotional symptoms in mothers. Intervention effects were less pronounced six months later, suggesting that FPPE may require booster sessions or function best as an add-on to other interventions, especially those without a family- or relationship-oriented component.</p>