Background: University students belong to the life stage of early adulthood, where they are required to establish a right attitude and value system about sexual matters. When teenagers go to college, they have more chances to contact with the other sex and become to live a relatively freer life, which make them face novel situations of dealing with sexual issues. Sexual assertiveness is a mandatory communication strategy for university students, especially for female students, who are living in this rapidly changing sexual culture. So, this study aimed to examine the relationship among appearance satisfaction, self-esteem and sexual assertiveness and identify the influencing factors on sexual assertiveness in female university students. Methods: A total of 166 female undergraduate students participated in this study. Data were collected through self-reported questionnaires consisted of the Body Esteem Scale, Self-esteem Scale, and Sexual Assertiveness Scale, between September and October 2018. Data were analyzed with SPSS/WIN25.0 for descriptive statistics using t-test, one-way ANOVA, Pearson's correlation coefficient, and multiple linear regression. Results: Sexual assertiveness was positively correlated with appearance satisfaction (r=.50, p<.001) and self-esteem (r=.64, p<.001). Multiple regression showed that satisfaction with major (β=.12, p=.043) and self-esteem (β=.10, p<.001) explained 48.3% of the variance in sexual assertiveness (F=52.28, p<.001). Conclusions: Thus, in order to improve sexual assertiveness, it may be helpful to positively accept one's appearance and self-esteem and to incorporate appearance satisfaction and self-esteem when planning to counseling and intervention about sexual assertiveness for female university students.