蔡仲，姬姓，名胡，西周人，蔡国第二任国君。

胡的父亲蔡叔度在三监之乱后被周公旦流放。蔡叔度死后，胡改进了品行，「率德驯善」，周公旦知道后，举荐他出任鲁国的卿士。胡使鲁国治理得很好，在周公旦的建议下，周成王把蔡地封给胡为国，是为蔡仲。

Cai Zhong Hu (Chinese: 蔡仲胡, lit. "Hu, Elder of Cai"), born Ji Hu (姬胡), was the only known son of Ji Du, the first lord of Cai.

Ji Du was removed from his office after participating in the Rebellion of the Three Guards against the regency of the Duke of Zhou. His son, however, became known as an honest and kind-hearted man, and was sent by the Duke of Zhou to Lu as an ambassador. Following this, King Cheng restored his father's fief to him and his son inherited it after him.