Pu-erh, Pu'er tea, Puer tea or Bolay tea is a type of tea made from a "large leaf" variety of the tea plant Camellia sinensis and named after Pu'er county near Simao, Yunnan, China.

Pu-erh tea can be purchased as either raw/green (sheng) or ripened/cooked (shu), depending on processing method or aging. Sheng pu-erh can be roughly classified on the tea oxidation scale as a green tea, and the shou or aged-green variants as post-fermented tea. The fact that pu-erh fits in more than one tea type poses some problems for classification. For this reason, the "green tea" aspect of pu-erh is sometimes ignored, and the tea is regarded solely as a post-fermented product. Unlike other teas that should ideally be consumed shortly after production, pu-erh can be drunk immediately or aged for many years; pu-erh teas are often now classified by year and region of production much like wine vintages.

While there are many counterfeit pu-erhs on the market and real aged pu-erh is difficult to find and identify, it is still possible to find pu-erh that is 10 to 50 years old, as well as a few from the late Qing dynasty. Indeed, tea connoisseurs and speculators are willing to pay high prices for older pu-erh, upwards of thousands of dollars per cake.