Introduction: This is a cross-sectional research on the impact of academic stress to which Peruvian students of dentistry are exposed and the various risk factors that affect academic performance and clinical and preclinical training. Aim: The aim of this study is to determine the association of the perceptions of stress and the risk factors in students who take preclinical and clinical courses of a Peruvian private university. Materials and methods: This cross-sectional study evaluated 222 students of the School of Dental Medicine at the Universidad Privada de Ciencias Aplicadas (UPC). To measure stress levels, we used the Dental Environment Stress (DES) questionnaire that was previously validated in Spanish. Data, such as age, sex, and year of study, were collected in a file made for this study. The students belonged to the 1st and the 5th year of study and authorized their participation through informed consent. In the data analysis, the odds ratio and the Chi-square test were used. Results: We found that clinical students have 2.96 times higher risk of having stress than preclinical students. Within these categories, in the preclinical level, the first-year students show the higher stress levels (68.2% in moderately stressful and very stressful 15.1%), while in the clinical level, the third-year students had a higher stress level (80.9% in moderately stressful and 19% in very stressful). Our data show no association between sex and stress levels of the students (p = 0.508). Conclusion: Clinical students show more stress level with 2.96 times higher risk for stress compared to preclinical students. In the preclinical level, the first-year students showed a higher stress level, while in the clinical level, third-year students had a higher stress level. Our data show no association between sex and stress levels of students. Clinical significance: The impact of stress on dentistry students significantly influences their performance at the time of performing dental treatment protocols. This research shows the direct relationship that exists between these variables.