This study used data from 845 foreign-born (n = 328) and native-U.S. born (n = 517) Hispanic mothers who participated in the Fragile Families and Child Wellbeing Study (FFCWS) to examine four indicators of acculturation--nativity, years lived in the United States, religious attendance, and endorsement of traditional gender norms--as predictors of maternal physical aggression directed toward young children. The authors also examined whether psychosocial risk factors associated with child maltreatment and acculturation--maternal alcohol use, depression, parenting stress, and intimate partner aggression and violence--mediate relationships between acculturation and maternal aggression. Foreign-born Hispanic mothers had significantly lower rates of physical aggression than native-born Hispanic mothers. In path modeling results, U.S. nativity, along with maternal alcohol use, parenting stress, and child aggressive behavior, emerged as the strongest risk factors for maternal physical aggression. Among the four acculturation indicators, only foreign birth was directly associated with lower maternal aggression. Study findings suggest immigrant status is a unique protective factor that contributes to lower levels of physical aggression among Hispanic mothers.