Evidence suggests that differentiation of self, a construct from Bowen's family system's theory, is predictive of college students' vocational identity and career indecision (Johnson, Schamuhn, Nelson, & Buboltz, 2014). However, the specific mechanisms within the relationships among differentiation of self and vocational identity as well as career indecision have received minimal attention. I proposed that goal instability, a construct of Kohut's self-psychology, could further explain the influence of differentiation of self on these career outcomes. I aimed to investigate how differentiation of self related to goal instability and ultimately how both of these influenced vocational identity and career indecision. Two hundred sixty-four traditional-aged (i.e., 18-24 years old) college students participated in the current survey. Participants completed demographic information, Differentiation of Self Inventory--Short Form (DSI-SF; Drake, Murdock, Marszalek, & Barber, 2015), Goal Instability Scale (GIS; Robbins & Patton, 1985), Vocational Identity (VI; Holland, Daiger, & Power, 1980), and Career Indecision Profile--Short (CIP-S; Xu & Tracey, 2017) using an online survey system. A path analysis revealed that goal instability mediated the overall relationships between sub-dimensions of differentiation of self, including emotional reactivity, emotional cutoff, I-position, and fusion with others, and vocational identity. Likewise, goal instability mediated the overall relationships between sub-dimensions of differentiation of self and four sources of career indecision, such as neuroticism/negative affectivity, choice/commitment anxiety, interpersonal conflict, and lack of readiness. The results provided empirical support for Bowen's proposition that well-differentiated individuals are goal- and principle-oriented (Frost, 2014), and suggested that goal instability functioned as one of the critical mechanisms to explain how differentiation of self related to career indecision issues among traditional-aged college students. Limitations, ideas for future research, and clinical implications were discussed. [The dissertation citations contained here are published with the permission of ProQuest LLC. Further reproduction is prohibited without permission. Copies of dissertations may be obtained by Telephone (800) 1-800-521-0600. Web page: http://www.proquest.com.bibliotheek.ehb.be/en-US/products/dissertations/individuals.shtml.]