All students studying Computer Science (CS) deserve to have their basic psychological need for belonging satisfied. In this dissertation, I present two studies of belonging among CS students at the University of Washington-Paul G. Allen School of Computer Science and Engineering. In the first study, my collaborators implemented a resubmission policy in introductory CS courses. My collaborators and I ran a large-scale, end-of-term survey asking students about their reasons for resubmission. We then interviewed nine students about the resubmission experience. In the second study, I studied students and teaching assistants (TAs) in 4 CS courses, including introductory, intermediate, and advanced; core and elective, interviewing them about their belonging in post-secondary CS. I conducted semi-structured 1:1 interviews with 14 participants, consisting of 7 pairs of students and TAs who interacted in office hours. I found that given the Allen School's competitive program, resubmissions take the pressure off the need to submit work that earns a perfect grade the first time, and that belonging may exist alongside preparatory privilege in some students. Nevertheless, my findings suggest that resubmissions alone can't create space for belonging, but that collaboration and relationships can. However, organic collaborations were inhibited by a strong fear of risking academic misconduct. I also found that student and TA conceptions and narratives of belonging aligned with the three basic needs for wellness as described in Self-Determination Theory: relatedness, competence, and autonomy. TAs and students reported that TAs supported student sense of belonging by fostering understanding of material, treating them with empathy, helping them see peers positively, and helping them to own their own success. Therefore, I claim the following thesis statement: In post-secondary computer science, both course policies and direct interactions with instructors and peers can contribute to the satisfaction of psychological needs for competence, relatedness, and autonomy, which can contribute to student sense of belonging. [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.]