[Correction Notice: An Erratum for this article was reported in Vol 49(1) of Developmental Psychology (see record 2013-00166-002). In the article, Study 2 is mistakenly described as a 9-month longitudinal study. However, this study covered 11 months.] The present research focuses on 2 factors that might help or hurt women to cope with the uncertainties associated with developmental transitions in modern societies (i.e., starting one's first job, graduating from high school, reentry to work after parental leave). We investigate (a) the role of openness to experience in coping with challenging transitions and (b) the (mal)adaptive consequences of adopting a traditional gender ideology. Starting with the assumption that transitional uncertainty has different consequences for women high or low in openness to experience, a first experiment (N = 61; 18–30 years) demonstrated that self-efficacy and well-being decrease after being confronted with transitional uncertainty among women low in openness. Two longitudinal studies investigated the (mal)adaptive consequences of adopting a traditional gender ideology for women high or low in openness in dealing with challenging transitions. Study 2 examined whether endorsing or rejecting traditional gender role beliefs might help female (but not male) students to maintain a sense of self-efficacy and subjective well-being during the transition of graduating from high school (N = 520, 17–22 years). Study 3 (N = 297; 20–53 years) tested the same model for women in middle adulthood during the transition from parental leave to reentry into work life. For both studies, latent growth analyses showed that endorsing traditional gender role beliefs contributed to self-efficacy and subjective well-being among women low in openness. By contrast, for women high in openness, rejecting traditional gender role beliefs had a positive effect on their relative level of self-efficacy and subjective well-being. Functions of ideologies in the context of challenging transitions are discussed.