This study examined parental depression and parental reflective functioning (PRF) as predictors of parental proficiency in relational savoring (RS), the association between RS proficiency and a marker of children's physiological self-regulation, respiratory sinus arrhythmia (RSA), during a stressor, and indirect effects of parental depression and PRF on children's RSA via parents' RS. At Time 1 (T1), parents of 8- to 12-year-old children (N = 139) reported on their depressive symptoms and completed a parenting interview, coded for PRF. After 1.5 years (Time 2; T2), parents savored a positive relational memory that involved their children, which was coded for savoring proficiency. Children's RSA was measured during a stressful task (a series of impossible puzzles). Depressive symptoms (inversely) and PRF (positively) were associated with RS proficiency. Higher parental RS proficiency was associated with children's higher mean levels of RSA during the stressor. Indirect effects models supported that T2 RS proficiency mediated the negative association between parental T1 depressive symptoms and children's T2 RSA, and between T1 PRF and children's T2 RSA. We discuss these findings in terms of implications for parents' emotion regulation, children's emotion regulation, children's mental health, and intervention.