Ohio State Route 571 is an east–west State Route highway in west-central Ohio, part of a state-wide road transportation system. It indirectly connects the cities of Union City and Greenville with Springfield via a final 10.7 miles (17.2 km) on U.S. Route 40. State Route 571 has many curves throughout its length, including dangerously sharp ones where many accidents have occurred, especially near the unincorporated village of Coletown in Darke County and east of Tipp City at State Routes 201 and 202.

State Route 571 starts in the Indiana/Ohio border town of Union City. To the west, it turns into Indiana State Route 28, which goes west toward Albany and Alexandria, Indiana. To the east, 571 goes southeast through Hill Grove and Coletown, and then parallels Greenville Creek into Greenville. From Greenville it continues southeast through Painter Creek and Laura to West Milton where it turns due east, passes over Interstate 75 to Tipp City and New Carlisle. About 3 miles (4.8 km) southeast of New Carlisle, Route 571 meets U.S. Route 40, the eastern terminus of the state route.

Although no longer a state route, the road keeps on going across US 40 as County Highway 303 "Medway-Carlisle Road" in Clark County. The road continues south, through the village of Medway and further on it turns into the northern terminus of Interstate 675 at Interstate 70.

It was part of the Pikes Peak Ocean-to-Ocean Highway which was completed in 1927. Before 1932 the portion of the route from Greenville to the Indiana state line was denominated route 29.

From 1932 to 1962, what is now State Route 571 was denominated State Route 71. The 71 number had to be retired following the opening of Interstate 71 through Ohio. State Route 571 was certified with its current (2007) route in 1962.

From 1938 to 1957 the highway in northwestern Ohio from 1-mile (1.6 km) south of Bridgewater Center to the Michigan state line, approximately a five mile (8 km) stretch, was denominated State Route 571. In 1957 that stretch was renumbered to become part of State Route 576.