Silicon carbide nanoparticles generally refer to particles about 1–100 nm in size and are single crystals in most cases. Silicon carbide nanocrystals (NCs) smaller than around 10 nm are also called SiC quantum dots (QDs). In this size regime, on account of the strong spatial confinement of carriers, SiC nanocrystals exhibit obvious quantum size effects, especially the quantum confinement effect. As a result, the energy gap of the silicon carbide nanocrystals widens and their interband transition luminescence shifts toward the smaller wavelength region (blue shift) gradually as their sizes diminish. In addition, their luminescence quantum yields may be improved by several orders of magnitude relative to that of the bulk materials. Note that when sizes of the NCs are only a couple of nanometers or even below one nanometer, the energy levels deviate from the quasi-continuous ones exhibited in bulk crystals and become more and more discrete with decreasing size owing to strong quantum confinement effect, being like those of big molecules.