Caring for older family members has become a focus of national attention among policy makers given concerns for the quality of life of both caregivers and care recipients. Although caregivers’ siblings often represent important ties for both the adult children providing care and parents receiving care, there has been limited attention to how siblings affect one another’s well-being during parent care. Guided by theories of identity and stress, the central aims of this dissertation are to investigate: (1) Whether perceiving care-related criticism from siblings is associated with higher depressive symptoms among adult children providing care to their mother; and (2) whether caregivers’ gender and the gender composition of the sibling networks in which they are embedded influence caregivers’ probability of perceiving care-related criticism from siblings. To achieve these aims, I utilize both quantitative and qualitative data collected from adult children providing care to their mothers as part of the Within-Family Differences Study-II. This mixed-methods approach enables me to not only examine statistical relationships, but also to identify mechanisms underlying these statistical patterns.Quantitative analyses revealed that perceived care-related criticism from siblings was not directly associated with caregivers’ depressive symptoms, but rather operated through its association with sibling tension. Consistent with theories of identity maintenance, qualitative analyses suggested that, in response to their siblings’ criticisms, caregivers often reacted in ways that may have been protective for their identity as a “good caregiver,” but that could have been a catalyst for sibling conflict and, in turn, psychological distress. Once perceived sibling criticism was established as a stressor with detrimental consequences for caregivers’ relational and psychological well-being, I then explored whether caregivers’ gender, as well as the genders of their siblings, shape caregivers’ probability of perceiving sibling criticism. As I anticipated based on theories of gender and group dynamics, daughters’ probability of perceiving sibling criticism depended on the gender composition of the sibling networks in which they were embedded; in particular, daughters in predominantly-son families had a notably lower risk of perceiving care-related criticism than daughters in families with a higher proportion of daughters. Consistent with theories of tokenism, qualitative data revealed that adult children in families with a higher proportion of daughters were less able to rely solely on gender stereotypes to shape caregiving expectations. As a result, there tended to be less consensus among siblings regarding who best understood their mother’s care needs and preferences, and higher rates of perceived sibling criticism among daughters.Taken together, these findings demonstrate the influence that identity processes, as well as the sibling networks in which caregiving takes place, have in shaping the experiences and consequences of parent care. This work demonstrates the value of utilizing a mixed-methods approach to gain a nuanced understanding of complex family processes. In addition, these findings offer valuable insights to health care professionals and other stakeholders who interact with and serve family caregivers. By understanding the mechanisms through which sibling context may contribute to psychological distress among caregivers, these stakeholders will be better prepared to identify and address caregivers’ socio-emotional needs.