This study explored the mediating role of career decision self-efficacy between core self-evaluations (CSE), a newly established construct within the personality domain, and adolescents' vocational identity. Using a sample of 200 Greek high school students, it was found that for female adolescents CSE influenced vocational identity both directly and indirectly (via career decision self-efficacy). For male students, CSE had only an indirect effect on vocational identity through career decision self-efficacy. The findings are discussed with reference to social cognitive career theory (SCCT) framework. Implications for research and adolescents' career counseling are also discussed. (Contains 2 tables and 1 figure.)