Purpose/objectives The coronavirus disease 2019 (COVID‐19) pandemic has presented mental health challenges among healthcare professionals, including posttraumatic stress disorder (PTSD). Few studies have examined PTSD predictors in dental settings. This cross‐sectional study aimed to describe the relationship between personality traits and PTSD symptoms among US dental residents engaged in patient care during the pandemic. Methods An online survey was administered to residents in advanced education in general dentistry, dental anesthesia, general practice residency, oral and maxillofacial surgery, and pediatric dentistry programs between September 2020 and April 2021. The survey included a sociodemographic questionnaire, the Big Five Inventory, and the PTSD Checklist for Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition . Logistic regression models, analysis of variance, and Tukey tests were used to examine the association between variables and PTSD scores and assess differences in personality traits and PTSD by specialty. Results Among 149 respondents (mean age = 29.9 ± 4.9 years; 57.0% female), 53.7% reported experiencing stress during the pandemic. Many residents (38.9%) were not aware of available mental health resources. A total of 17.4% of residents met the diagnostic criteria for PTSD, but only 1.3% reported a previous PTSD diagnosis. The most significant predictors of PTSD were neuroticism (odds ratio = 2.90, p = 0.046) and stress unrelated to the resident's program role during the pandemic (odds ratio = 5.88, p = 0.02). Conclusions PTSD symptoms were highly prevalent among dental residents, with stress and neuroticism being the most significant predictors.