Abstract Background Family caregivers may experience financial vulnerabilities due to their caregiving role, affecting their ability to afford appropriate food and ensure optimal nutrient intake. Therefore, this cross-sectional study aimed to assess the extent to which there are diet-related disparities among older family caregivers. Methods We included 125 family caregivers from Eastern Finland (mean age 74 y). Data on family caregivers’ health, nutritional status, and sociodemographic factors were collected at their households between June 2019 and December 2019. First, we assessed the sociodemographic factors associated with family caregivers’ inadequate diet. Then, we evaluated diet-related health disparities. The associations and predictors of diet-related disparities were assessed using the independent samples t-test, χ2-test, and binary logistic regression. Results The preliminary results show that family caregivers experiencing subjective poverty were less likely to consume two or more portions of fruit and vegetables per day (odds ratio = 0.11; 95% confidence interval 0.02-0.72; p = 0.021) and were more likely to be overweight. Furthermore, family caregivers’ inadequate diet (i.e., lack of daily fruit and vegetables and risk of malnutrition) was further associated with several health conditions, including comorbidity, depression, diabetes (type I and II), and osteoporosis. Conclusions Family caregivers have diet-related disparities, which may further lead to health inequalities. Family caregivers’ diet-related disparities require increasing attention in healthcare. Thus, addressing family caregivers’ food insecurity risk could enhance their health equity. Key messages • Older family caregivers’ inadequate diet is associated with social and health inequalities. • We must assess the root causes of diet-related disparities among older family caregivers and the broad consequences to find solutions to narrow the inequalities.