Masculine honor beliefs are the idea that masculinity needs to be earned, defended and maintained and that it is justified for men to reassert their threatened masculinity through displays of violence or aggression. Indeed, men adhering to these ideologies often distance from any association with threats to their masculinity such as femininity and seek to reinforce traditional masculine gender roles. Previous research has shown that greater masculine honor beliefs are also associated with greater endorsement of intimate partner violence. Expanding on previous research, we examined the relationships between masculine honor beliefs and third party participants’ perceptions of the acceptability of intimate partner violence based on the described masculinity of a man (high, low) and described femininity of a woman (high, low). We hypothesized that participants higher in masculine honor beliefs would be more likely to accept intimate partner violence, especially in the situation where the man is less masculine and the woman is more masculine because each presentation is a potential threat to the man’s masculinity. In the study, participants were randomly assigned to read one of the four vignettes (with the manipulated high or low masculinity level of the man and woman). The participants read four levels of aggression in the vignette: low, medium and high verbal aggression and physical aggression, and rated the acceptability of each action after reading each level. Consistent with previous research and our hypothesis, the results showed that higher levels of masculine honor beliefs were associated with greater endorsement of verbal aggression (but not physical) toward a woman, and this was especially true when the woman was described as being more masculine and when the man was described as being less masculine. Taken together, our findings highlight how adherence to traditional gender roles and the deviation from hegemonic gender norms can promote and impact the acceptability of aggression by those endorsing masculine honor-based ideologies.