Khlong Sok is a river in Khao Sok (fig.) which is formed by the confluence of Khlong Phra Saeng, which emerges from the Chiaw Lan Reservoir (fig.) at the Ratcha-prapha Dam (fig.), with the Phum Duang River.

The latter is a tributary of the Ta Pi River which empties in the Gulf of Thailand, near the city of Surat Thani. Due to its proximity to Khao Sok National Park, the Khlong Sok River is a popular venue for rafting, canoeing and river tubing.