A previous study suggested that mothers of 5-year-old children with borderline intellectual functioning displayed lower positive engagement with their children as compared with both mothers of typically developing children and mothers of children with significant developmental delays (Fenning, Baker, Baker, & Crnic, 2007). The current study integrated father data and followed these families over the subsequent 1-year period. Parent and child behavior were coded from naturalistic home observations at both waves. Results revealed that mothers of children with borderline intellectual functioning displayed a greater increase in negative-controlling parenting from child age 5 to 6 than did other mothers; fathers displayed more negative-controlling behavior in comparison to fathers of typically developing children. In addition, children with borderline intellectual functioning themselves exhibited a more significant escalation in difficult behavior than did typically developing children. Cross-lagged analyses for the sample as a whole indicated that maternal negative-controlling behavior predicted subsequent child difficulties, whereas negative paternal behavior was predicted by earlier child behavior. In conjunction with evidence from Fenning et al. (2007), these findings suggest a complex, dynamic, and systemic developmental pattern in the emotional behavior of families of children with borderline intellectual functioning. Implications and areas in need of additional research are discussed.