Background: Dental profession is labeled as a high-risk profession, due to which dental care professionals are under tremendous pressure during the outbreak of COVID-19 pandemic. The aim of this study was to assess the psychological impact of the COVID-19 pandemic on dental interns in Riyadh, Saudi Arabia. Materials and methods: A cross-sectional study was conducted among dental interns from different universities in Riyadh, Saudi Arabia. The data were collected using a validated Depression, Anxiety and Stress Scale-21 Items (DASS-21) questionnaire. Descriptive statistics were presented using frequencies (n) and percentages (%). Chi-square and Fisher exact tests were used to assess the association between sociodemographic data (age, gender, nationality, marital status, and history of physical and mental illness) and levels of depression, anxiety, and stress. A p < 0.05 was considered as statistically significant. Results: A total of 160 dental interns were invited to participate in this survey; out of which 110 participants responded yielding a response rate of 78%. The mean age of the study participants was 25.1 years. About 65% of the participants were female. Only 14.5% of the subjects reported having a past history of physical or mental illness. Depression, anxiety, and stress were identified in 11.9%, 7.3%, and 0.9% of the dental interns, respectively. Demographic characteristics did not appear to influence depression, anxiety, or stress levels (p > 0.05). Conclusion: The outbreak of COVID-19 pandemic has affected the mental health of dental interns. The presence of depression, anxiety, and stress among dental interns highlights the need for special intervention and support programs to promote mental health and well-being among dental interns.