Tofu, also toufu (the Japanese Romaji spelling), doufu (the Chinese Pinyin spelling often used in Chinese recipes) or bean curd (the literal translation), is a food of Chinese origin, made by coagulating soy milk, and then pressing the resulting curds into blocks. There are many different varieties of tofu, including fresh tofu and tofu that has been processed in some way. Tofu has very little flavor or smell on its own, so it can be used either in savory or sweet dishes, and is often seasoned or marinated to suit the dish.

The production of tofu from soy milk is similar to the production of cheese from milk (fermentation), although some tofu is made by processing non-soy products, such as almonds or black beans. Two major byproducts of the process are tofu skin and soy pulp.

Tofu originated in ancient China, but little else is known about the origins of tofu and its method of production. The origin is the source of some speculation and legend, but there is insufficient historical information to support such speculations. Tofu and its production technique were subsequently introduced into Japan in the Nara period (late eighth century) as well as other parts of East Asia. This spread likely coincided with the spread of Buddhism as it is an important source of proteins in the religion's vegetarian diet.

Tofu is low in calories, contains beneficial amounts of iron (especially important for women of child bearing age) and has no cholesterol. Depending on the coagulant used in manufacturing, the tofu may also be high in calcium (important for bone development and maintenance), and magnesium (especially important for athletes). However, tofu contains soy isoflavones, and the safety of consuming isoflavones is questioned.