The Batten Kill, Battenkill, or Battenkill River is a 59.4-mile-long (95.6 km) river rising in Vermont that flows into New York and is a tributary of the Hudson River. It is the longest Hudson tributary on that river's east. As "kill" means a creek, the name "Battenkill River" is pleonastic.

The mouth of the Batten Kill is in Easton, New York, and the source of the river is in East Dorset, Vermont.

The river is known for its fishing, as it has a prominent trout population. The Shushan Covered Bridge crosses it at one point. As does the Rexleigh Bridge.

The Batten Kill valley is home to the Tour of the Battenkill, the largest road cycling race in North America.^{[citation needed]}

The Native American name for the river is either Dionoondehowee or Ondawa.

The Batten Kill rises in East Dorset, Vermont, and flows south, with Mad Tom Brook soon joining it from the southern slope of Mount Tabor. It flows in a southwesterly direction to Arlington and then in a westerly direction, entering New York. The river continues west, forming the boundary between the towns of Jackson and Salem, turning north at the hamlet of Shushan. Turning west again at Greenwich Junction, the river becomes the boundary between Jackson and the town of Greenwich, passing the hamlets of East Greenwich, Battenville and Center Falls before reaching the village of Greenwich. The Batten Kill continues as the boundary between Greenwich and the town of Easton, past the hamlet of Middle Falls and ends at the Hudson River, at a point one mile (1.6 km) north of Schuylerville.

From source to mouth following the major windings, the river measures 59.4 miles (95.6 km). The length of the river in Vermont is approximately 28 miles (45 km).

The Vermont portion of the Batten Kill watershed drains much of the northern portion of Bennington County and includes an area of approximately 200 square miles (520 km²). The New York portion of the watershed covers 207 square miles (540 km²).