More than half of U.S. college students are first-generation students (i.e., without a parent who completed a bachelor's degree), yet these students are at increased risk compared to continuing-generation students for earning lower grades, not completing their degree, and lower life satisfaction. First-generation students are also less likely to use institutional resources when they need support, and parental support may be less useful given parents' limited college experiences. Yet, the potential value of sibling support has been understudied. The present study examined whether perceived sibling support was associated with self-esteem, life satisfaction, hope, and adaptive coping mechanisms among first-generation college students (n = 167). Overall, receiving more sibling support was associated with greater self-esteem, life satisfaction, hope, and the use of adaptive coping mechanisms, with some nuances based on gender and sibling structural characteristics. Thus, siblings may serve as important sources of support for first-generation college students' academic success and well-being.