Background: There is an increasing proportion of older people in the population worldwide, with a large group being dependent on the care of others. Dependent older people are more vulnerable to oral diseases, which can heavily impact their quality of life (OHRQoL) and general health. Objective: The purpose of this systematic review was to comprehensively assess interventions to improve oral health or guarantee access and adherence to dental treatment of dependent older people. Methods: We searched MEDLINE, EMBASE, CENTRAL and clinical trial registries. Two reviewers performed the selection, data extraction, risk of bias evaluation using the Cochrane Risk of Bias tool and assessment of certainty of the evidence. When possible, we conducted a meta-analysis to calculate effect estimates and their 95%CIs. Primary outcomes were OHRQoL, oral/dental health, and use of the oral care system. Results: We included a total of 30 randomised clinical trials assessing educational and non-educational interventions for community-dwelling older people (n = 2) and those residing in long-term care facilities (n = 28). Most studies assessed oral hygiene and showed that interventions may result in a reduction in dental plaque in the short term (with low certainty of evidence), but there is limited evidence for long-term effectiveness. Only one study assessed OHRQoL, and none evaluated changes in the use of the oral health care system. Conclusion: Our findings do not provide strong conclusions in favour of any specific intervention, mainly due to study quality and imprecision. There is limited information about the long-term effect of interventions, and further research is needed, especially targeting community-dwelling older people. PROSPERO ID: CRD42021231721.