Background <p>Globally, the demand for nursing home care workers is rapidly increasing due to population ageing, higher patient acuity, and growing concerns regarding workload. Prior research, predominantly focused on registered nurses, suggests these high demands and increased workloads could lead to essential care tasks being left undone and heightened risks of emotional exhaustion. This study aims to examine the association between unfinished care and risk of burnout among care workers in nursing homes and to evaluate whether managerial support moderates these associations.</p> Methods <p>We conducted a cross-sectional, multicenter study, using survey data retrieved from 56 Belgian nursing homes between May and December 2021. We assessed self-reported unfinished care, burnout risk, managerial support, and sociodemographic variables of 1,054 care workers (registered nurses, nursing assistants and allied health professionals). We applied two-level linear mixed models to account for data clustering. Models were built in three stages: (1) estimating the association between unfinished care subscales and burnout outcomes; (2) adding managerial support; and (3) introducing unfinished care × managerial support interaction terms to test moderation, consistent with the Job Demands–Resources framework.</p> Results <p>We explored the associations between unfinished care and burnout, and found all domains of unfinished care to be positively associated with the risk of emotional exhaustion and depersonalization, and negatively associated with personal accomplishment. Stratified analyses showed that favorable managerial support tends to attenuate these associations with risk of depersonalization, while unfavorable support was likely to amplify the strength of these associations.</p> Conclusion <p>Our findings underscore the importance of minimizing unfinished care, as it is regarded as an indicator of quality, and is significantly associated with all dimensions of risk of burnout. Managerial support appears to act as a buffer in this association, with unfavorable support exacerbating the effects, particularly with regard to depersonalization. Conversely, these effects are attenuated when care workers perceive their manager as supportive, emphasizing the value of supportive leadership. Implications for practice include informing and training care managers on how to foster a more participative and supportive work environment.</p>