Toward advancing conceptualizations of the spillover hypothesis, this study examined the conditions and mechanisms underlying the transmission of distress from the interparental relationship to parenting difficulties over a 2-year period in a sample of 233 mothers (M = 35.0 years) and fathers (M = 36.8 years) of kindergarten children. Findings from autoregressive structural equation models indicated that parents' gender moderated associations between interparental conflict and parental psychological control and insensitivity to children's negative affect. Pathways between interparental conflict and parenting difficulties over the 2-year period were significant for fathers but not mothers. Analysis of insecurity and depressive symptoms as affective mechanisms of spillover revealed that adult relationship insecurity was a significant mediator in the pathways between interparental conflict and parenting difficulties experienced by fathers. (Contains 2 tables and 2 figures.)