Aims: This study determined the knowledge, attitudes, and practices regarding COVID-19 and assessed the acceptance of the COVID-19 vaccine among the elderly in Chiang Mai, Thailand. Instrument & Methods: From February to May 2021, a cross-sectional study was conducted among 450 elderly 60 years old and above who lived in Chiang Mai Municipality. The questionnaire collected demographic characteristics, knowledge, attitude, practice about COVID-19, and acceptance of the COVID-19 vaccine. Descriptive statistics are used to analyze. Findings: The results showed that 48. 4% of the participants were male, 51. 6% were female, and the mean± SD age was 68. 2± 7. 3 years. Participants have sufficient knowledge, attitude, and practice about COVID-19, and the mean± SD score is 9. 7± 1. 3, 4. 2± 0. 8, and 3. 98± 0. 5, respectively. The mean± SD score of the knowledge, attitude, and acceptance of the COVID-19 vaccine were 4. 3± 1. 4, 2. 9± 1. 9, and 2. 2± 0. 9, respectively. This study's major issue is 95. 1% of people strongly agree that maintaining social distancing can protect them and their families from contracting COVID-19, and 92. 7% strictly follow the guidelines to prevent the spread of COVID-19. The policy can ultimately control the disease. 81. 3% of respondents acknowledged vaccines are vital to the health of the elderly and believe that vaccination can reduce morbidity and mortality. Also, 75. 8% of people know that the COVID-19 vaccine can cause side effects. Conclusion: The elderly in Chiang Mai, Thailand, have adequate knowledge and awareness about COVID-19 and are generally optimistic about resolving the pandemic and addressing the public concerns, raising awareness about COVID-19 vaccination as a disease-control method to prevent further deterioration of general public health due to COVID-19.