This dissertation builds on and extends research on the relationship between equity-minded mathematics teaching, specifically teaching mathematics for social justice, complex instruction, and project-based learning, and students' learning and identity development. Although different in their structures and strategies, equity-minded mathematics teaching approaches focus on supporting historically marginalized students to see themselves as capable learners, does, and users of mathematics by challenging power structures that perpetuate inequity within mathematics and mathematics classrooms. Three manuscripts, which attend to how students who are historically marginalized in mathematics negotiate the focus on identity and power within equity-minded mathematics teaching approaches, make up the main portion of this dissertation. Each manuscript is a self-contained empirical study, with its own research questions addressed through relevant literature, data sources, analysis, findings, and discussion. The first manuscript explores the possibilities and limitations of teaching mathematics for social justice to address racially-based inequities and injustices, in mathematics education and in society more broadly. Through a metasynthesis of thirty-five qualitative reports of social justice mathematics enactments in diverse classroom contexts, findings illuminate a set of evidence-based, promising practices that might help teachers manage tensions that arise when integrating mathematics goals and social justice, towards ensuring anti-racist enactments of teaching mathematics for social justice. The context for the other two manuscripts was a 9th grade geometry class in a STEM-themed, open-enrollment magnet school with a diverse racial and ethnic student population. The teacher in this classroom strove to create an environment that encouraged out-of-school experiences and identities as part of mathematics activity by using a hybrid blend of project-based learning, complex instruction, and teaching mathematics for social justice. Over a yearlong ethnography, I observed classroom interactions and relationships, which were recorded through field notes, photos, and video, and I conducted interviews with individual students and focus groups. The analysis framed learning as identity development, which was operationalized using a figured worlds theoretical framework. The second manuscript in this dissertation describes how students collectively negotiated the emphasis on identity and power across three project-based learning projects, which integrated complex instruction strategies and focused on exploring social justice questions about access to quality and affordable food. The third manuscript focused specifically on the voice of Black girls and their construction of "hands on" mathematics as humanizing within the project-based learning context. Together, findings amplify the voices and experiences of students who are historically marginalized in mathematics and contribute to the field's understanding of how students can reconstruct intended instructional goals and approaches on their own terms. The other two chapters in this dissertation include an introduction and conclusion. The introduction provides an overview of this dissertation and describes how I came to this work. The concluding remarks summarize and synthesize the three empirical studies and offer possibilities for moving forward into an Assistant Professor position. [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.]