OBJECTIVES: Vaccine hesitancy may represent a barrier to effective COVID-19 immunisation campaigns. This study assesses individual, disease-specific and contextual factors associated with COVID-19 vaccine acceptance among a nationally representative sample of older Brazilian adults. DESIGN: Cross-sectional analysis of data from household interviews and a supplementary telephone survey. SETTING: Brazil and its five geographic regions. PARTICIPANTS: Data are derived from 6584 individuals aged 50 years and over who participated in the second wave of the Brazilian Longitudinal Study of Aging. PRIMARY AND SECONDARY OUTCOME MEASURES: Survey-weighted multinomial logistic regression assesses factors associated with intending, not intending or being uncertain about one's intention to vaccinate against COVID-19. FINDINGS: Seventy-one per cent of study participants intend to receive a COVID-19 vaccine once available, while 17% (representative of nearly 9 million people) have no intention to vaccinate, and 12% are still undecided. Besides age, demographic and health-related factors related to COVID-19 severity and complications were not associated with intention to vaccinate. Those who most trusted social media or friends and family for COVID-19 information and those who did not trust any information source were 68% and 78% more likely to refuse vaccination, respectively, as compared with those who trusted official information sources. People who inconsistently used face masks when outside were 3.4 times more likely than consistent face mask users to intend to refuse vaccination. Higher municipal COVID-19 fatality rates were negatively associated with vaccine refusal. CONCLUSIONS: Most national COVID-19 immunisation strategies identify older individuals as among those prioritised for early vaccination, given their increased risk of more severe symptoms and complications of the disease. Because individual, disease-specific, and contextual factors were associated with vaccine acceptance, there is a clear need for multilevel and multichannel information and outreach campaigns to increase COVID-19 vaccine acceptance among vulnerable older populations.