Objective To explore the mediating effect of perceived social support between growth mindset and impostor feelings of nursing undergraduates, and to provide guidance for mental health education to reduce impostor phenomenon.Methods A conve-nience sample of 1 085 undergraduate nursing students from five medical colleges in Jiangsu Province was surveyed from October to November 2024.Participants completed a demographic questionnaire, the Clance Impostor Phenomenon Scale (measuring impostor feelings), the Growth Mindset Scale, and the Perceived Social Support Scale.Mediation analysis was conducted using AMOS 28.0.Results Mean scores of the instruments were as follows: impostor feelings 53.21±11.45, growth mindset 17.02±4.24, and perceived social support 67.34±11.37.Impostor feelings score was negatively correlated with both growth mindset and perceived social support (both P＜0.05).Perceived social support partially mediated the effect of growth mindset on impostor feelings, accounting for 14.09% of the total effect.Conclusion Undergraduate nursing students have medium level of impostor feelings.Perceived social support partially mediates the relationship between growth mindset and impostor feelings among undergraduate nur-sing students.Nursing educators should emphasize social support education and cultivate growth mindsets to alleviate impostor feelings and promote professional growth.