Indiana University-Purdue University Indianapolis (IUPUI) / Women are underrepresented in science, technology, engineering, and math fields (STEM), especially in higher levels. Researchers term this phenomenon "the leaky pipeline." While the issue is well-documented in the literature, little is known about its antecedents. The current study offers insight into factors that relate to career choice and contribute to the lack of diversity in STEM fields by investigating how sense of belonging and psychological capital (PsyCap) influence important psychological, academic, and career outcomes for women in these fields. Female undergraduate STEM majors were recruited for participation at two times during the fall academic semester (N=182 at time one, N=86 at time two) and data were analyzed using correlation and regression. Results provide support for the influence of both sense of belonging and PsyCap as important correlates of an individual's academic and career making decisions. Specifically, PsyCap mediated the relationship between belonging and well-being and belonging and career outcomes of engagement and participants' intentions to apply to graduate programs in an unrelated major. In addition, PsyCap moderated the relationship between sense of belonging and participants' intentions to switch majors and intentions to apply to graduate programs in a field unrelated to their current major. An increased understanding of the factors that contribute to the leaky pipeline in STEM will serve as a basis for developing further research questions and targeting interventions.