This study sought to understand how doctoral students in mathematics education learn to become equity-oriented mathematics teacher educations (EOMTEs) by analyzing the experiences of current doctoral students in mathematics education at three universities across the US. I focus on doctoral students learning in mathematics education because doctoral students often go on to become mathematics teacher educators, therefore providing doctoral students in mathematics education with the potential to influence the practices and dispositions of future mathematics teachers. I used case study tradition to investigate the communities of practice (CoP) doctoral students participate in that support their learning and the ways doctoral student identities as EOMTEs develop related to engagement, alignment, and imagination (Wenger, 1998). I found two kinds of CoPs that support doctoral student learning to become EOMTES: institution-based mixed member and peer created CoPs. Institution-based mixed member CoPs provided opportunities for doctoral students to learn to apply theories into practice and expand their conceptions of what it means to be an EOMTE. Key features of productive institution-based mixed member groups are (1) there are shared interests in collaboration by all members, regardless of their status in the group, (2) participants perceive that all members of the CoP have shared understandings and commitments to equity, (3) new members learn the norms of participation in these groups by observing the interactions between more veteran members, and (4) these groups have knowledgeable and experienced members who guide the learning of novice members. Peer created CoPs are established when doctoral students feel a necessary part of their learning is missing from the institution-based mixed member CoPs they participate in. Key features of productive peer created CoPs are (1) the learning focuses on a genuine interests of the doctoral students in the group, (2) members can opt-in or opt-out with no social or academic consequences, and (3) members perceived they have similar status. Additionally, findings indicate there are specific ways an identity as an EOMTE is either encouraged or discouraged in doctoral student experiences. I found evidence that when doctoral students have both meaningful opportunities to engage in practice as EOMTEs and feel their beliefs and stances are aligned with other members of the CoP, then there are opportunities for doctoral students to imagine themselves in increasingly sophisticated roles as EOMTEs. Conversely, if there is a lack of either meaningful opportunities of engagement or alignment between the doctoral student and other members of a CoP, imagination is limited. [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.]