Purpose/objective: The purpose of this study was to assess the frequency of unmet needs of carers among a convenience sample of carers, and the participant factors associated with unmet needs, to inform the development of interventions that will support a range of caregivers. The aims of this study were to: (1) assess the most frequently reported moderate-high unmet needs of caregivers; and (2) examine the age, gender, condition of the care recipient, and country variables associated with types of unmet needs reported by informal caregivers. Research method/design: An online cross-sectional survey among informal caregivers in English-speaking countries was conducted. Self-reported unmet needs were assessed using an unmet needs measure with the following five unmet needs domains: (1) Health information and support for care recipient; (2) Health service management; (3) Communication and relationship; (4) Self-care; and (5) Support services accessibility. Informal caregivers were asked "In the last month, what was your level of need for help with...", and the ten highest ranked moderate-high unmet needs presented as ranked proportions. Logistic regression modelling examined the factors associated with types of unmet needs. Results: Overall, 457 caregivers were included in the final analysis. Seven of the ten highest ranked unmet needs experienced by caregivers in the last month were in the Self-care domain, including "Reducing stress in your life" (74.1%). Significant associations were found between younger caregiver age (18–45 years) and reporting moderate-high unmet needs in Health Information and support for care recipient, Health service management, and Support services accessibility (all p's = <0.05). Conclusions/implications: Caregivers are not experiencing significant differences in unmet needs between countries and caree/care recipient conditions, suggesting that general interventions could be developed to support a range of caregivers across countries. Increased awareness of informal caregivers' unmet needs, particularly for younger caregivers, among health care providers may improve support provision to caregivers.