Community colleges offer access to higher education for many who otherwise would not be able to attend college, including academically underprepared students, students from low-income backgrounds, and place-bound adults. Recently, some community colleges have diverged from this historical mission and embraced "mission expansion." Examples of mission expansion in the community college context include the community college baccalaureate (CCB), campus housing, and other programs or policies typically associated with four-year colleges and universities. To date, research on mission expansion in community colleges has been limited. Using a college-level panel dataset for academic years 2001-02 through 2020-21, I conducted three studies to understand better the "landscape," "antecedents," and "outcomes" of mission expansion in U.S. community colleges. I found that most community colleges engaged in mission expansion, albeit to a limited degree, and that engagement in mission expansion has increased over the past two decades. Practical considerations, such as financial challenges and pressure from nearby colleges, largely motivated engagement. Still, mission expansion was not central to most community colleges' identities. Notably, many community colleges simultaneously pursued mission-expansive initiatives while maintaining commitments to mission-consistent functions, and adverse effects on community colleges' access mission were evident but limited. These findings speak to an understudied development in the community college sector, and advance our understanding of mission change among U.S. colleges and universities by incorporating the experiences of a sector often overlooked in discussions of mission change. Findings also have practical implications for community college decision-makers and stakeholders. [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.]