This study explored the relationships of maturity fears and appearance interest(interest in appearance, interest in weight) with self-concept among girls with precocious puberty. The participants for this study were 120 elementary school students (8 to 10 years old) and their parents from two hospitals located in Chungcheong Province. Data were collected from January to February 2019 using self-reported questionnaires. The collected data were analyzed using descriptive statistics, the independent t-test, the Mann-Whitney U test, one-way analysis of variance, Pearson correlation coefficients, and multiple regression analysis in SPSS for Windows version 23.0. Statistically significant negative correlations were found between self-concept and maturity fears (r=-.34, p<.001) and interest in weight (r=-.29, p=.001). Maturity fears were identified as a factor affecting the self-concept of girls with precocious puberty (β=-.34, p<.001). This variable explained 11.5% of the variance in the self-concept of girls who experienced precocious puberty. This study confirmed that maturity fears had a major influence on self-concept in girls with precocious puberty. The results of this study can be used as basic data for the development of a psychosocial nursing intervention program for girls who experience precocious puberty.