Given the increasing prevalence of people with dementia in long-term care, various educational interventions have been developed to enhance the dementia care competence of healthcare providers. The study aim was to appraise the evidence of the effects of dementia care educational programs on improving the preparedness of nursing home staff. Articles on dementia care education interventions for nursing home staff were searched from eight databases. The primary outcomes were staff knowledge, attitude, competence, and sense of competence or self-efficacy related to dementia. The secondary outcomes were psychological outcomes, including burnout, caregiving stress, well-being, and job satisfaction. The quality of evidence was appraised using the Joanna Briggs Institute Critical Appraisal tool. Out of the 3269 articles identified, 19 randomized controlled trials comprising 3947 participants from eight countries were included. The methodological quality of included studies was fair. A significant improvement in staff knowledge regarding dementia was reported. The intervention effects on attitudes and competence were insignificant, and the effects on the sense of competence or self-efficacy related to dementia care were inconsistent. The effects on psychological outcomes seem limited because few significant changes were found. Multiple teaching methods, peer support, qualified trainers, and post-training support were effective components in designing the educational interventions. However, given the variations in content and dose and the methodological limitations of the included studies, the effects of educational programs were inconclusive. The findings highlight the necessity of high-quality studies on dementia-care educational interventions, especially in other cultures than Western countries, such as in Asia.