The purpose of this research is to investigate the relations between gender roles, career self-efficacy, and career development of STEM gifted girls in high schools and universities in Taiwan, from a developmental perspective. It includes two studies. In Study 1, 473 gifted girls from eight high schools in Taiwan participated, and, based on a self-reported survey, the results indicated 52.5% possessed neutral characteristics and it also implied that they simultaneously possessed masculine and feminine characteristics. Meanwhile, the higher the social gender-role awareness and career self-efficacy, the better was that individual's career development. However, when compared to gifted girls in language/social sciences, the career self-efficacy and career development of STEM gifted girls was significantly lower. Later, 70 gifted girls continually participated in Study 2, on a voluntary basis. We found that although STEM gifted girls had their own goals and direction when it came to universities, the higher they are in the education stage, the lower the career self-efficacy and lower science learning interest they may have. This would have a certain degree of impact on their subsequent career development. Thus, a well-designed career program and mentorship for gifted girls are needed to address the current issue.