Purpose: Online schools were initially designed to provide access to diverse courses to advanced and homeschooled students, however, many online schools now market their programs specifically to students whose needs place them at-risk in traditional schools. The capacity of technology to address any of the needs of under-served students is largely undetermined and it is unclear if online schools are in fact enrolling significant proportions of these students. Furthermore, little is known about the ways in which online schools are supporting the needs of the under-served students they are enrolling. The purpose of this study is to establish how and in what ways online schools serve under-served students. Given the almost complete absence of research at the intersection of under-served students and online learning, a descriptive analysis is an appropriate place to start. Data Collection and Analysis: This study was conducted in two phases. First, a near-census of state level enrollment and demographic data identifying students enrolled in Virtual Schools in most of the states authorizing full-time online schools was completed by examining state websites and surveying state department of education staff. Second, case study analysis of four schools in different U.S. regions was completed, including in-depth interviews with administrators, teachers, support staff and students. Online and face-to-face classes and learning sites were observed. Schools were selected from states offering full-time online options and based on their enrollment of under-served students. Findings: In this study I define what under-served students need as four separate but interdependent components: "adequate resources," "fair systems," "excellent teaching" and "culturally responsive" practices. In each component I analyze the ways in which online learning can specifically contribute. The reoccurring theme observed in 3 out of the 4 schools studied, however, is that technology's potential is barely reflected in online schools. Practitioners are still using online technology to deliver an education system firmly rooted in conventional school practices leaving the potential of online technology still untapped. However, one school--Blended Virtual H.S.--consistently pushes itself to more fully garner technology's potential in innovative and substantive ways and their staff appreciates, challenges and is ready to empower their students. [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/en-US/products/dissertations/individuals.shtml.]