According to gender role theory, individuals who confirm expectations associated with their gender roles are rewarded and judged against these expectations when they deviate. Parental roles are strongly tied to gender, and there are very different expectations for behaviors of mothers and fathers. This study examined how mothers' and fathers' behaviors that support or discourage a positive relationship with the other parent are perceived in terms of their acceptability. Two-hundred twent-eight parents completed an online survey assessing perceptions of acceptability of negative ( parental alienating) and positive coparenting behaviors. Results provided support for our hypothesis: Although parental alienating behaviors were rated unacceptable, they were more acceptable for mothers than fathers. Expectancy violation theory can explain why parental alienating behaviors are not viewed as negatively when mothers exhibit them than fathers.