Workers often strive to achieve the financial and psychological benefits that are associated with career success. Accordingly, organizational scholars have investigated the determinants of advancement in organizations. However, despite the increasing proportion of working parents and the potential incongruity between involvement in family and success at work, little research has directly considered the effects of parental status and responsibilities on advancement. This study examines the extent to which both genuine (i.e., self-reported) and perceived (i.e., supervisor-reported) behaviors and attitudes about work and family influence the success of working parents. As such, this is the first study to consider the relative importance of supervisor perceptions of work-family constructs in determining career success. Furthermore, drawing from social role theory, it is predicted and found that stereotypes about working mothers drive biased perceptions about their work attitudes and behaviors. Thus, this research provides empirical evidence to support the widely-held assumption that one mechanism underlying the "maternal wall" is bias toward working mothers.