The prevalence of serious mental illness (SMI) is rising among midlife adults in the United States. Recent supporting evidence uncovers gender differences in overall prevalence and an unexpected relationship with education. For the current midlife cohort, women were the driving force behind growing postsecondary enrollment during a time of rapid change to the educational landscape. Using data from High School & Beyond (HS&B), the present study explores the relationship between exceeded adolescent educational expectations and midlife SMI among women. For women in the HS&B sophomore cohort, exceeding expectations is significantly associated with increased odds of experiencing SMI in midlife compared to those who met their educational expectations. This study provides new insight into the relationship between misaligned educational expectations and SMI through the extension of analyses into midlife, consideration of exceeded expectations as a category for misalignment, and focus on women.