The COVID-19 pandemic is a public health emergency of international concern. Due to the nature of the clinical treatment, dentists are among those at high-risk to contract the disease. However, there is scant data on dentists’ concern about getting COVID-19 infection from their practice and the associated factors. This study aimed to investigate the concern about getting COVID-19 disease in Thai dentists, along with the associated factors. A questionnaire was developed and distributed via social media from April 24 to May 5, 2020. The dentists’ working and sociodemographic status were collected as independent variables. Two numerical scale-rated questions were asked to assess the level of concern about getting infected from daily and clinical activities. Two open-end questions about the source of unpleasantness and opinion of the pandemic were also included in the questionnaire. Of 622 responses, 580 were included in the final analysis. Thai dentists had more concern about contracting the disease from performing dental treatment (score 6.80±2.58) than doing daily activities (score 5.15±2.65), P<0.001. Female dentists had a significantly higher concern about contracting the disease than males, P<0.001. A significant negative correlation with age was found, P<0.001. Thai dentists are concerned about COVID-19 infection from performing the dental treatment to a higher degree than from daily activities. Age and sex were related factors.