Manganese (Mn)-based materials have been extensively investigated for a wide range of biomedical applications owing to their remarkable catalytic chemistry, magnetic resonance imaging (MRI) capacity, biodegradability, low toxicity, and good biosafety. In this review, we first elaborate on the catalytic principle of Mn-based nanoenzymes for antitumor and antibacterial therapy, followed by a comprehensive discussion of the interesting structural design engineering strategies used to achieve multi-dimensional Mn-based nanoarchitectures, such as zero-dimensional (0D) nanoparticles, 1D nanotubes, 2D nanosheets, 3D hollow porous Mn ball, and core-shell nanostructures. Moreover, the therapeutic applications of different Mn-based nanoenzymes, including manganese dioxide (MnO