Background Accurate pain assessment is essential for effective pain management and quality patient care. While various demographic and psychological factors influence clinical skills, the specific role of self-compassion in shaping nursing undergraduates' perspectives remains underexplored. Aim To evaluate the effect of self-compassion and demographic factors on how nursing students perceive pain assessment. Methods A descriptive, cross-sectional design was utilized for this study, conducted at a university nursing department in Türkiye during the 2023–2024 academic cycle. The target population comprised 172 undergraduates with prior clinical experience. From this group, 141 individuals were recruited via convenience sampling. To gather data, three instruments were administered: a demographic questionnaire, the “Nursing Students’ Attitudes Scale Toward Pain Assessment”, and the “Self-compassion Scale”. Analyses encompassed descriptive statistics, correlational tests, and multivariate linear regressions. Results Participants achieved an overall mean score of 64.42 ± 9.18 (min = 25; max = 75) on the pain assessment attitude scale, and 2.82 ± 0.38 (min = 2.08; max = 4.00) on the self-compassion scale. Analysis revealed that age and gender served as significant predictors of pain assessment attitudes (F = 5.931; p < 0.05). In contrast, self-compassion levels and academic year showed no significant predictive value (p > 0.05). Conclusion Participants displayed highly favorable attitudes regarding pain assessment alongside moderate levels of self-compassion. Female participants and older students exhibited significantly more positive attitudes. Notably, a student's degree of self-compassion had no significant influence on their overall approach to evaluating pain.