Ge ware or Ko ware is a type of celadon or greenware in Chinese pottery. It was one of the Five Great Kilns of the Song dynasty recognised by later Chinese writers, but has remained rather mysterious to modern scholars, with much debate as to which surviving pieces, if any, actually are Ge ware, whether they actually come from the Song, and where they were made. In recognition of this, many sources call all actual pieces Ge-type ware.

Celadon is a term for pottery denoting both wares glazed in the jade green celadon color, also known as greenware or "green ware", and a type of transparent glaze, often with small cracks, that was first used on greenware, but later used on other porcelains. Celadon originated in China, though the term is purely European, and notable kilns such as the Longquan kiln in Zhejiang province are renowned for their celadon glazes. Celadon production later spread to other parts of East Asia, such as Japan and Korea, as well as Southeast Asian countries, such as Thailand. Eventually, European potteries produced some pieces, but it was never a major element there. Finer pieces are in porcelain, but both the color and the glaze can be produced in stoneware and earthenware. Most of the earlier Longquan celadon is on the border of stoneware and porcelain, meeting the Chinese but not the European definitions of porcelain.