Tsai Hong-tu (Chinese: 蔡宏圖; pinyin: Cài Hóngtú; born 1 August 1952) is a Taiwanese businessman and banker. He is a son of Tsai Wan-lin, the former richest person of Taiwan who died in 2004.
Tsai Hong-tu is the chairman of the board of Cathay Financial Holdings. Inherited stakes of the company with brothers Tsai Cheng-da and T. Y. Tsai when father Tsai Wan-lin died in 2004. Family also controls Cathay Real Estate, a Taiwan property developer. In 2010's Forbes World's Billionaires List, Tsai was ranked no. 582 in the world, side by side with brothers Tsai Cheng-da and T. Y. Tsai, each with individual net worth of 1.7 Billion US Dollar.