Purpose: This study aimed to examine the level of perceived stress, interpersonal competence, adaptive cognitive emotional regulation, and mental health and identify factors that influence mental health of Korea Armed Forces Nursing Academy (KAFNA) cadets. Methods: A descriptive predictive design was used. Data were collected using questionnaires from a convenience sample of 169 KAFNA cadets in 2021. The data were analyzed using descriptive statistics, t-test, ANOVA, Pearson correlation coefficients, and multiple linear regression. Results: The mean scores of the perceived stress, interpersonal competence, adaptive cognitive emotional regulation, and mental health were 1.99, 3.42, 3.78 and 0.28 respectively. Mental health differed significantly according to religion (F=-2.04, p=.039). Mental health correlated with perceived stress (r=.70, p<.001), interpersonal competence (r=-.34, p<.001), and adaptive cognitive emotional regulation (r=-.37, p<.001). Multiple regression analysis showed that mental health accounted for 57.0% of the variance by perceived stress, interpersonal competence, adaptive cognitive emotional regulation, and religion (F=56.44, p<.001). Conclusion: The results of the study show that perceived stress, interpersonal competence, and adaptive cognitive emotional regulation are important determinants of mental health in KAFNA cadets. These findings suggest that strategies focused on positive cognitive evaluation in stressful situations, and interpersonal relationship should be developed for KAFNA cadets to promote their mental health.