BACKGROUND: There is widespread hesitancy towards COVID-19 vaccines in the United States, United Kingdom, and Australia. OBJECTIVE: To identify predictors of willingness to vaccinate against COVID-19 in five cities with varying COVID-19 incidence in the US, UK, and Australia. DESIGN: Online, cross-sectional survey of adults from Dynata's research panel in July-September 2020. PARTICIPANTS, SETTING: Adults aged 18 and over in Sydney, Melbourne, London, New York City, or Phoenix. MAIN OUTCOMES AND MEASURES: Willingness to receive a COVID-19 vaccine; reason for vaccine intention. STATISTICAL METHODS: To identify predictors of intention to receive a COVID-19 vaccine, we used Poisson regression with robust error estimation to produce prevalence ratios. RESULTS: The proportion willing to receive a COVID-19 vaccine was 70% in London, 71% NYC, 72% in Sydney, 76% in Phoenix, and 78% in Melbourne. Age was the only sociodemographic characteristic that predicted willingness to receive a COVID-19 vaccine in all five cities. In Sydney and Melbourne, participants with high confidence in their current government had greater willingness to receive the vaccine (PR=1.24; 95% CI=1.07-1.44 and PR=1.38; 95% CI=1.74-1.62), while participants with high confidence in their current government in NYC and Phoenix were less likely to be willing to receive the vaccine (PR=0.78; 95% CI=0.72-0.85 and PR=0.85; 95% CI=0.76-0.96). LIMITATIONS: Consumer panels can be subject to bias and may not be representative of the general population. CONCLUSIONS: Success for COVID-19 vaccination programs requires high levels of vaccine acceptance. Our data suggests more than 25% of adults may not be willing to receive a COVID-19 vaccine, but many of them were not explicitly anti-vaccination and thus may become more willing to vaccinate over time. Among the three countries surveyed, there appears to be cultural differences, political influences, and differing experiences with COVID-19 that may affect willingness to receive a COVID-19 vaccine.