Although worldwide practices of inclusive education aim to provide equal learning opportunities for students with special educational needs (SEN) to support their learning performance in schooling, comparatively less is known about these students' competences in preparing and achieving their post-secondary school outcomes. This study extended previous research on testing ordinary secondary students' career development self-efficacy to the population of students with special educational needs. Participants were grades 9 to 12 SEN students in Hong Kong. Eight types of SEN were included. The Career Development Self-Efficacy Inventory (CE-SEI) assessed five key domains of career development self-efficacy (i.e., career planning, career goal setting, training selection, job hunt preparation, and job hunting). The confirmatory factor analysis supported the consistency of internal structure of this instrument in SEN students. The correlation analysis showed statistically significant correlations among the five key factors of career development. This study has practical implications to help school stakeholders to develop effective career guidance to support SEN students by using this validated short form of CE-SEI as a useful screening tool to diagnose pre-existing problems of SEN students' career development self-efficacy. Implications of this study are also discussed in relation to current implementation of career guidance and lifelong education policy in secondary schools.