Background: The existing literature is dominated by models of parent-child aggression (PCA) risk using maternal samples, thereby limiting insight into factors that contribute to fathers’ PCA risk. Protective factors that can affect PCA risk within the mother-father dyad at the cultural level are also often overlooked. Objective: The current study examined the potential positive role of gender ideologies on maternal and paternal PCA risk over time, considering both individual and partner effects on PCA risk. Participants and setting: Participants were 150 couples, with primiparous mothers and their male partners identified from a larger study of PCA risk. Methods: The study employed a longitudinal design with three waves. Participants were first assessed in mothers’ third trimester of pregnancy and re-assessed when their child was 6 months and 18 months. Dyads reported their gender role attitudes prenatally and PCA risk across time. Results: Egalitarian gender role ideologies related to lower PCA risk for both mothers and fathers prenatally. At 6 months, neither mothers’ nor fathers’ gender role ideologies related to PCA risk but by 18 months, fathers’ gender role beliefs predicted their PCA risk whereas mother's gender role beliefs only marginally predicted their PCA risk. Maternal egalitarian gender ideologies significantly predicted fathers’ lower PCA risk at 6 months. Conclusions: These findings suggest less traditional gender roles may contribute to lower PCA risk in parents particularly prior to childbirth. Therefore, future work is needed to further consider the evolving interconnectedness within couples in their PCA risk over time.