Caregiving research has not accounted for increasingly diverse and complex marital and family histories of older Americans. The authors examined social relations and care-specific positive and negative support networks among late-life remarried wife dementia caregivers (N = 61) to determine associations among network structure, relationship quality with and support received from network members, and global assessments of family and stepfamily disagreement on caregiver well-being. Own family and friends predominated in the social relations and positive networks. Although over half (54%) of respondents included a stepfamily member in their positive networks, stepchildren comprised the largest group (35%) in the negative networks. Larger negative networks and actively negative interactions were related to greater caregiver burden, and more global disagreement with stepfamily was associated with greater depression and burden. The findings illustrate the complex nature of support and the value of targeted examinations of caregiving support dynamics among late-life remarried older adults and stepfamilies facing health demands.