The undermatch between low-income students' academic achievement and college destinations has become increasingly important in discussions of higher education access and equity. This study investigates whether low-income students are undermatched in their college choice, and if so, what factors are related to the undermatching. Specifically, this study examines the timing and reasons for low-income students to leave from the process of selective college access (i.e., qualification, application, admission, and enrollment). The study used data from the Education Longitudinal Study 2002 (ELS: 2002) and the sample of this study includes 12,270 students who were seniors in 2004. Discrete time event history analysis was applied. Regardless of family income, the stage of qualification was the most hazardous followed by the stage of application and the stage of admission was the least hazardous. Low-income students had lower odds of being qualified for, applying to, being admitted in, and enrolling at a selective institution(s) than high-income students, and the largest gap among income groups was found in the stage of qualification. Gender, race/ethnicity, parental education, academic ability, the quality of high school attended, the proximity to a selective institution, and the number of peers aspiring to four-year college education were associated with selective college access. Disadvantages in these factors further limited low-income students' access to selective higher education. Overall, the current research revealed the tendency of undermatching for low-income students and structural barriers directly or indirectly resulting in undermatching. As a way to resolve the structural barriers, the study recommends to create a comprehensive and uniform secondary school system with equal funding for public schools, to provide sufficient college guidance and counseling to the disadvantaged students, and to increase the opportunities of participating extracurricular activities. [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://bibliotheek.ehb.be:2222/en-US/products/dissertations/individuals.shtml.]