Jiexi County () is a county of eastern Guangdong province, China. It is under the administration of Jieyang City.
Immigrants from Jiexi form a large overseas Chinese population who speak the Hepo dialect of Hakka (70%), mainly in Sarawak, Johor and Negeri Sembilan (Malaysia), and Bangka Belitung, Sumatra (Indonesia). Other people from Jiexi speak the Teochew dialect (30%). In the late 18th and early 19th century, settlers from Jiexi county formed the Lintian kongsi republic, an autonomous polity named after a temple in Jiexi dedicated to the Lords of the Three Mountains in Jieyang (揭阳霖田祖庙).
Jiexi is home to the Huangmanzhai waterfalls. There are ambitions to make Jiexi County a more attractive tourist destination following investment in 2010.
The Lords of the Three Mountains (, also Kings of the Three Mountains) are a triad Taoist deities worshiped in Southern China (mainly Teochew people) and the part of Hakka people in Taiwan. The Three Mountains refer to 3 mountains in Jiexi Co