Dental students are known to experience certain stress during their training, which a peak stress level is reported in the fifth year. Currently, the COVID-19 pandemic situation has affected them in all dimensions including stress. This research is a cross-sectional study on fifth-year dental students in Thailand that aimed to evaluate the effect of the COVID-19 pandemic on stress levels in the fifth-year dental students in Thailand. However, this study is a preliminary report of the dental students who are currently studying in Bangkok and its vicinity. Stress level, related factors, and source of news were collected from June to December 2020 through online questionnaires. Order regression statistic was used to analyze the stress level and related factors. Participants included 179 students from 6 universities, which was accounted for 35.87% of the population. The participants consisted of 129 (72.07%) females and 50 (27.93%) males with an average age of 23.7 (21-34) years. The results indicated that 41.31% of these students had high stress (level 3) and 38.55% had severe stress (level 4). Regarding stress contributing factors, the odds ratio of the concern about the inadequate time for clinical practice and deterioration of health were 7.198 and 2.353 (p<0.001), respectively. The main sources of news were Twitter, followed by Facebook. The emergent COVID-19 pandemic that brought preventive measures required during the outbreak increased the stress in the 5^th year dental students. Expectantly, a realization of their stress level and stress contributing factors can urge for appropriate intervention to reduce their stress. Besides, effective sources of news will be helpful to guide them through this difficult period.