According to the recent MAA National Study of College Calculus (Bressoud, Mesa, & Rasmussen, 2015) more than a third of US Calculus I students come in contact with undergraduate mathematics peer tutors (UMPTs) and mathematics tutoring has the ability to influence affect as well as academic learning, but, undergraduate mathematics tutoring is under researched (Mills, Tallman, & Rickard, 2017). We need to understand the context and UMPTs' identities in order to shape best tutoring practices and inform future research. This dissertation is an ethnography of a mathematics learning center (MLC) at a public university examined from the perspective of the UMPTs and through the theoretical perspective of figured worlds. Data was collected in the form of field observations, a survey distributed to tutors in the center, and a series of case studies. Four tutors were observed tutoring. They participated in stimulated recall interviews about their tutoring, and completed a semi-structured final interview. One primary finding is that the MLC plays an important social role for UMPTs beyond its academic and professional function and that they desire students to enter into similar enactments as found in their mathematical community. This was apparent in the participants' descriptions of the physical space, cultural artifacts, key social groups, and in analysis of both tutoring and non-tutoring enactments that took place in the MLC. The mediating role of cultural artifacts authored roles of autonomy for students and facilitated collaboration and community. UMPTs navigate a role as "almost peers" within their tutoring interactions in the MLC. Their identity enactments require significant and ongoing negotiation as they feel students may enter the MLC with different goals and attempt to position themselves and tutors in alternative roles. UMPTs emphasize understanding mathematics and students having a positive affect as central goals in their tutoring interactions. These results yield several implications for practice within MLCs. Suggestions are also made for future research on UMPTs and MLCs including further considering their non-academic/social roles for both undergraduate tutors and students seeking tutoring. [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.]