Tetsubin are Japanese cast iron pots having pouring spout and handle crossing over the top, used for boiling and pouring hot water for drinking purposes, such as for making tea. Because iron is released into the water, the water is appreciated as a dietary source of iron.

Tetsubin traditionally are heated over a charcoal fire. In the Japanese art of chanoyu, the special portable brazier for this is the binkake. (See list of Japanese tea ceremony equipment).

Tetsubin are often elaborately decorated with relief designs on the outside. They range widely in size, and many have unusual shapes, making them popular with collectors. A relatively small tetsubin may hold around .5 litres of water; large ones may hold around 5 litres.

Tetsubin can be found in many colors with various designs and patterns such as this red one that has symbols depicting each of the four seasons for good luck.

The historical origin of the tetsubin is not certain. At least one authoritative Japanese source[ states that it developed from the spouted and handled water kettle called tedorigama that was already being used in chanoyu in the era of Sen no Rikyu (1522-91). During the 19th century, infused tea became more popular and tetsubin were considered primarily status symbols rather than functional kitchen items.

There is also a kind of relatively small cast iron pot that resembles a tetsubin but is glazed with enamel on the inside in order to lend itself to making brewed tea, and is referred to as an iron kyusu or teapot. Most often, however, ceramic is used for making kyusu. Kyusu often come with a tea strainer that fits inside.

The prefectures of Iwate and Yamagata are best known for producing tetsubin as well as iron kyusu.