The vast underrepresentation of minority, first-generation, and low-income students in postgraduate programs is cause for serious concern in the growing workforce. Despite the increase of college enrollment among underrepresented first-generation, low-income (UFGLI) students over the last decade, there are still a disproportionately small percentage of UFGLI students in postgraduate education, such as doctoral, professional, and masters-level programs. These educational disparities significantly affect opportunity for societal advancement and power. Findings from previous literature reveal that UFGLI college students often lack access to resources that provide assistance in the pursuit of postgraduate studies and that UFGLI students encounter additional barriers during the postgraduate application process compared to their more privileged peers. This study includes an in-depth discussion on the barriers that students encounter throughout the application process and introduces a new construct to the literature that may impact students’ entrance into postgraduate programs: postgraduate school application self-efficacy. While previous scholars have explored the admissions processes for a variety of disciplines and have developed a measure for graduate education self-efficacy, no measure has been developed to assess postgraduate school application self-efficacy (PSASE). Therefore, the purpose of this study was to develop a valid and reliable measure of students’ postgraduate school application self-efficacy. In order to accomplish this, parallel analyses and exploratory factor analyses were conducted to determine the underlying structure of the PSASE scale, Cronbach’s alpha was computed to examine the scale’s internal consistency, and correlational analyses were conducted to demonstrate convergent and divergent validity. Results revealed a conceptually interpretable, five-factor solution that accounted for 75.43% of the total variance. The 25-item measure contained items with high factor loadings, low cross-loading, and strong construct coverage. The subscales all demonstrated strong internal consistency and cohesiveness. Correlational analyses with two similar, but distinct, constructs (graduate education academic self-efficacy and self-esteem) provided evidence of convergent and discriminant validity for the PSASE subscales and total scale. Implications and future directions were also explored.