Background: Moral distress is considered to be the negative feelings that arise when one knows the morally correct response to a situation but cannot act because of institutional or hierarchal constraints. Objectives: To analyze moral distress and its relation with sociodemographic and academic variables in undergraduate students from different universities in Brazil. Method: Quantitative study with a cross-sectional design. Data were collected through the Moral Distress Scale for Nursing Students, with 499 nursing students from three universities in the extreme south (...) of Brazil answering the scale. The data were analyzed in the statistical software SPSS version 22.0, through descriptive statistical analysis, association tests (t-test and analysis of variance), and linear regression models. Ethical considerations: Approval for the study was obtained from the Research Ethics Committee at Universidade Federal do Rio Grande. Findings: The mean intensity of moral distress in the constructs ranged from 1.60 to 2.55. As to the occurrence of situations leading to moral distress in the constructs, the frequencies ranged from 1.21 to 2.43. The intensity level of moral distress showed higher averages in the more advanced grades of the undergraduate nursing course, when compared to the early grades of this course (between 5 and 10 grade, average = 2.60–3.14, p = 0.000). Conclusion: The demographic and academic characteristics of the undergraduate nursing students who referred higher levels of moral distress were being enrolled in the final course semesters, were at a federal university, and had no prior degree as an auxiliary nurse/nursing technician. (shrink)