PURPOSE: The purpose of this study was to investigate effects of leadership, critical thinking disposition, and professional self-conception of nurse on happiness in nursing students. METHODS: Data ware collected from 160 nursing students from March to May 2015, using self reported questionnaire. Descriptive statistics, t-test, ANOVA, correlation analysis and multiple regression were used to analyze the collected data. RESULTS: Happiness in nursing students was correlated with leadership (r=.68, p < .001), critical thinking disposition (r=.36, p < .001) and professional self-conception of nurse (r=.57, p < .001). Factors significantly influencing happiness in nursing students were leadership (β=.48, p < .001), professional self-conception of nurse (β=.17, p=.032) and life satisfaction (β=.18, p=.003), with a total explanatory power of 53.0%. CONCLUSION: The results of this study showed that leadership, critical thinking disposition, and professional self-conception of nurse should be promoted to increase happiness of nursing students.