Oldest‐old individuals are a growing segment of the population that faces several challenges in terms of care demands. Informal caregivers experience more or less challenges, namely depending on the support they can access. The present study explores the unmet needs of a sample of informal caregivers of community‐dwelling older adults aged 80+ and analyses the association of such needs with sociodemographic information, care‐giving context (e.g., length of care),and health characteristics of the caregivers and care receivers (e.g., cognitive status and functionality). We recruited 175 care‐giving dyads from the North of Portugal. Descriptive statistics summarised the sample's characteristics. Informal caregivers were mainly women with a mean age of 60.6 years (SD = 9.8). Care receivers' mean age was 88.7 years (SD = 5.6) and were functionally dependent (9.3 points [SD = 7.0] and 27.0 points [SD = 3.5] for Basic and Instrumental Activities of Daily Living, respectively). A thematic analysis of an open‐ended question on unmet needs was performed, revealing the presence of unmet needs. The most relevant ones (financial support, caregiver support, primary care/medical specialities, and labour regulation) were further analysed, concerning the care‐giving dyad's using Independent Student's t test or Mann–Whitney U Tests, and Chi‐squared test or Fisher's Exact test depending on the variable. The most frequent unmet needs were associated with the caregiver's age, care receivers' kinship, number of care‐giving hours, the caregiver's gender, professional status, the caregiver strain and medicines intake. Findings suggest the need for establishing policies that ensure adequate sustainability of the provision of informal care that takes into account the needs of care‐giving dyads in the planning process.