Yong Saetae (Thai: หยง แซ่แต้; Chinese: 鄭鏞,^[1] Teochew: Dên Iong; ?–?) was a Chinese merchant and the father of King Taksin the Great. The Vietnamese called him Trịnh Yển (鄭偃).^[2][3]

His birth name was Dên Dag (Chinese: 鄭達; pinyin: Zhèng Dá). Born in Chenghai County, Chaoshan, China.^{[4]: 112 [5][6]} It was said that he was a broad-minded and unconventional man. His fellow countrymen did not like him, and called him Pai Gian Dag (痞囝達 or 歹子達, lit. "Dag, the ruffian"^[7] in Teochew).^[1] he came to Siam to do business,^[8][9] and became rich, and changed his name to Yong Saetae. Later, he became a tax-collector,^[10]: 770 and married a wealthy royal woman Nok-lang (later Princess Phithak Thephamat), who later gave birth to Taksin.^[1][11]