Objectives We provide national estimates of caregiving networks for older adults with and without dementia and examine how these networks develop over time. Most prior research has focused on primary caregivers and rarely on change over time. Method We identify a cohort of older adults continuously followed in the National Health and Aging Trends Study between 2011 and 2015 and receiving help from family members or unpaid caregivers in 2015 (n = 1,288). We examine differences by dementia status in network size, types of assistance and task sharing, and composition—differentiating between "specialist" and "generalist" caregivers helping in one versus multiple activity domains. Multinomial regression is used to estimate change over time in network task sharing and composition. Results In 2015, older adults with dementia had larger caregiving networks involving more task sharing than those without dementia and more often relied on generalist caregivers, especially the subset assisting with medical, household, and mobility or self-care activities. Uniformly greater reliance over time on these more intensely engaged generalist caregivers chiefly accounts for larger dementia networks. Discussion Findings lend support to the need for caregiver training on managing multiple task domains and—for dementia caregivers in particular—task-sharing skills. More generally, the design of new approaches to better support older adults and their caregivers should consider the complexity, heterogeneity, and change over time in caregiving networks.