The purpose of this study was to describe d/Deaf and Hard of Hearing (d/DHH) students' and an instructor's perceptions of "teaching presence" and "social presence" in online learning environment. A focus on education of underrepresented populations coupled with d/DHH student preference to take online courses creates a need for more research-based best practices addressing the diverse needs students who are d/Deaf or Hard of Hearing (d/DHH).Through the use of a single case-study design, this study explores two elements of the Community of Inquiry framework - teaching presence and social presence - in an online course designed for students who are d/DHH. The unit of analysis was an 8-week, 3 credit, Collaborative Online International Learning (COIL) course specifically designed for d/DHH students in the US and Norway. Through interviews and observation of the course and class interactions, the study generated rich data addressing the instructor's and students' perceptions of "teaching presence" and "social presence" in online learning environment. Results of the study show d/DHH students' perceptions towards instructor strategies to set up a collaborative space in online learning environment. The findings of the study suggest that d/DHH students needs are met when a course has clear navigation, and content along with assignment descriptions are delivered in multiple formats (ASL video and text). Students feel welcomed when the Deaf culture is recognized and appreciated and when they're given the opportunity to share about their personal and professional lives. Instructors should proactively address the areas mentioned above to create online collaborative experiences conducive to learning among d/DHH 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://bibliotheek.ehb.be:2222/en-US/products/dissertations/individuals.shtml.]