The type and frequency of children's exposure to intimate partner violence (IPV) are considered as key variables in understanding children's heightened risk of externalizing symptoms. Notably, children's exposure to IPV has been primarily measured using mothers' reports of their own victimization. However, mothers and children might differently perceive children's exposure to physical IPV. To date, no research has investigated multi-rater reporting discrepancies in child's exposure to physical IPV and whether such discrepancies would be linked to externalizing symptoms. This study aimed to identify patterns of mother-child discrepancies in child's exposure to physical IPV and examine whether those patterns would be associated with children's externalizing symptoms. Participants were mothers who have experienced police-reported male-perpetrated IPV and their children (n = 153; 4-10 years). Latent profile analysis identified three profiles of mother-child discrepancies: a concordant group reporting high IPV exposure; a discordant group with mothers and children reporting high and low child's IPV exposure, respectively; a second discordant group with mothers and children reporting low and moderate IPV exposure, respectively. Profiles of mother-child discrepancies were differentially associated with children's externalizing symptoms. Findings suggest that discrepancies among informants' ratings of children's IPV exposure might have important implications for measurement, assessment, and treatment.