Pure zirconia will transform into different phases, which include monoclinic, tetragonal, and cubic, at different high temperature levels. Specific phases can be retained at room temperature by adding stabilizer and yttria is one of the most common stabilizers for zirconia, commonly formed yttria stabilizer zirconia (YSZ). To utilize YSZ in various industry applications, the amount of yttria and sintering temperature played a vital role. Thus far, YSZ has received a warm welcome in the industries of thermal barrier coating (TBC), solid oxide fuel cell (SOFC), and biomaterial. However, the limitations and challenges still occur, and this opens up the room and possibility of enhancing and improving the material properties of YSZ for a better performance in the mentioned area. This chapter explained the working principles of YSZ in the industries respectively and the research been conducted to improve the materials accordingly.