In a sample of 559 children (ages 9–18), researchers investigated whether: (a) fear of abandonment mediated the association between postdivorce interparental conflict (IPC) and mental health problems, and (b) parent–child relationship quality moderated the association between IPC and fear of abandonment. Mediation analyses indicated that pretest IPC predicted fear of abandonment 3 months later, which then predicted child‐ and teacher‐reported mental health problems 10 months later. The hypothesized protective effect of a high‐quality parent–child relationship was not observed. IPC predicted fear of abandonment for all children, except for those with low‐ and moderate‐quality father–child relationships, for whom IPC was not significantly related to fear of abandonment. Findings highlight the need to optimize child coping programs and improve parenting‐after‐divorce programs to reduce IPC.