Abstract The spin Hall effect of light (SHEL) is the microscopic splitting of light into two circular polarizations at the optical interface along the perpendicular direction. With the advent of metamaterials/metasurfaces and their fast‐developing applications, the SHEL has been garnering significant scientific interest. Here, the principle and recent developments in SHEL research is reviewed. A theoretical description of the SHEL is provided, including the formalism and general techniques. Also, recent studies on and applications of the SHEL are extensively reviewed, including the enhancement of the spin Hall shift and efficiency, implementation of dynamic tunability, elimination of polarization dependence, and precision measurements. The review is concluded with a discussion on the future direction and prospects of the SHEL.