In this chapter, a few XR apps that have been developed to support mathematics learning will be reviewed. In the discussion of each app, the design framework for deep learning with XR apps is used to identify some of the strengths and constraints of each app with a note that the analysis is based on what could be inferred from the available descriptions. Based on the assessment of the related research literature in the case of mathematics, it is clear more small- and large-scale evidence of their effectiveness is needed, especially how the content/curriculum/task, app, and assessment components of the design framework can be aligned and developed in ways that support the simultaneous evolution of and growth in learners’ thinking and reasoning and their intra-actions in the XR environment. Furthermore, more classroom-based implementation research studies around sustained use of such apps will also help establish their important, and perhaps necessary, role in supporting students’ learning of mathematics.