Due to projected growth of the 65-and-older population and concerns of an impending care gap, reliance on informal caregivers is expected to increase. Improving support for informal caregivers is viewed as a national priority, yet research related to the unmet support needs of informal caregivers is limited. The purpose of this cross-sectional correlational study was to examine predictive relationships between contextual factors (caregiving relationship and type of illness) and environmental factors (rurality) and the unmet support needs (classes, service access, support groups, counseling, and respite) of informal caregivers of older adults. The theoretical framework was Bronfenbrenner’s ecological systems theory. Archival data were drawn from the 2015 Behavioral Risk Factor Surveillance System optional caregiver module dataset provided by the Centers for Disease Control and Prevention. Findings from multiple logistic regression analysis revealed that spousal caregivers had 42.7% lower odds than adult child caregivers of reporting unmet support needs related to service access. Dementia caregivers had 2.05 times higher odds of reporting unmet support needs of counseling, 1.31 times higher odds of reporting unmet support needs related to service access, and 1.91 times higher odds of reporting unmet support needs for respite care, relative to other caregivers. Caregivers residing in a suburban county had 28.7% lower odds and caregivers not residing in a metropolitan statistical area (MSA) had 30.5% lower odds of reporting unmet support needs related to service access, relative to caregivers residing in the center city of an MSA. Health care leaders and policymakers may use the findings to distribute resources and tailor interventions to better meet the needs of informal caregivers of older adults.