The Little Hocking River is a small tributary of the Ohio River, long, in southeastern Ohio in the United States. Via the Ohio River, it is part of the watershed of the Mississippi River, draining an area of on the unglaciated portion of the Allegheny Plateau. The river flows for its entire length in southwestern Washington County; its tributaries also drain a small area of southeastern Athens County.
The Little Hocking River begins in Fairfield Township between the communities of Barlow and Bartlett and initially flows southeastward through southwestern Barlow Township into Dunham Township, where it is dammed to form Veto Lake, which is surrounded by the Veto Lake State Wildlife Area. Downstream of Veto Lake, the river flows southwestward into Belpre Township; near its mouth it turns eastward and flows into the Ohio River at the community of Little Hocking.
Among the Little Hocking River's tributaries are three with names derived from that of the main stream: The East Branch Little Hocking River begins at in Warren Township and flows southwestward to in Dunham Township. It is long and drains an area of . The Little West Branch Little Hocking River begins at in Fairfield Township and flows southward through Decatur Township to in Belpre Township. It is long and drains an area of . The West Branch Little Hocking River begins at in near Bartlett in Wesley Township and flows south-southeastward through Fairfield and Decatur Townships to in Belpre Township. It is long and drains an area of .
According to the Geographic Names Information System, the Little Hocking River has also been known historically as "Little Hockhocken River," "Little Hockhockin River," and "Little Hockhocking River."