The central research question for this dissertation is: "How do overseas Christian ESOL teachers describe putting their religious beliefs into practice in their profession?" Specifically, the focus is on mostly evangelical Christian English language teachers who have earned a TESOL certificate and who at the time of this project were working overseas in non-religious higher education settings in Vietnam, Cambodia, and Laos. The main rationale for asking this research question is this dissertation's claim that personal religious beliefs need to be explored within the professional domain of teacher knowledge, as initially argued in the literature review. Data analysis and interpretation demonstrate that this study's participants link these categories of beliefs in ways that are complex and illuminating. The connections these overseas teachers make help explain how they know what they know and why they do what they do as TESOL professionals; that is to say, the data demonstrate substantial interrelationships among participants' personal religious beliefs and their professional teacher knowledge. Findings are reported in three ways: (1) qualitative themes, namely professionalism, relationality, and witness; (2) individual case studies of four teacher participants; and (3) issues for cross-case comparisons, namely distinctiveness and witness, applied theology and witness, and professionalism and witness. Finally, three key issues are revisited for additional, open-ended discussion. The first issue is the predominantly inward-focused nature of the findings. This may be a limitation in this project's data or of the topic itself. The second issue is the controversy over Christian witness in TESOL, initially described in the literature review and highlighted in the findings. The third issue is the larger issue of how beliefs are put into practice. Discussion of these three issues aims to highlight and broaden the significance of this dissertation's research and to suggest ways forward for future research and discussion. [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.]