Background: In rural communities around the world, individuals with serious health problems and their family caregivers often experience greater barriers to healthcare access. Identifying unmet support service needs of rural-dwelling caregivers can reveal intervention and policy targets. We examined unmet needs reported by rural caregivers in the U.S. Methods: We used data from the 2015-2018 U.S. Behavioral Risk Factor Surveillance System that included the optional caregiving module (32 U.S. states, D.C. and Puerto Rico). We identified rural caregivers using metropolitan statistical area (rural) and the item, "During the past 30 days, did you provide regular care or assistance to a friend or family member who has a health problem or disability?" Logistic regression models incorporating sampling weights provided adjusted odds ratios (adjusted ORs) of factors associated with having any unmet support service needs, and specific need types: classes about giving care, help with service access, support groups, individual counseling, respite. Factors included sociodemographic (gender, race/ethnicity, age, education, income, employment, marital status) and caregiving-related (intensity [±20 hours/week and ±2-year duration], caregiver-care recipient relationship, and main health problem) variables. Results: Of the 8,651 rural caregivers (representing 2.3 million) included, 16% endorsed unmet needs. Help accessing services was the most common need, followed by support groups and individual counseling. Factors associated with higher odds of any unmet need included Black vs. White race (adjusted OR: 1.74 [95%CI: 1.21-2.50]), college vs. high school graduate (adjusted OR: 1.85 [1.37-2.52]), and higher vs. lower intensity caregiving (adjusted OR: 2.18 [1.27-3.73]). Conclusions: Many U.S. rural caregivers report unmet support service needs. Future interventions to benefit rural caregivers should target individuals and communities with the highest unmet needs.