Pennsylvania Route 346 (designated by the Pennsylvania Department of Transportation as SR 0346) is a 34-mile (55 km) state highway located in Warren and McKean counties in Pennsylvania, United States The western terminus is at the New York state line in the Allegheny National Forest, where it becomes New York State Route 280. The eastern terminus is at an intersection with PA 446 in Eldred.

PA 346 was assigned in the original assignment of state highways in Pennsylvania. It originally began in Foster Brook, north of Bradford, and ended in Eldred. It was extended westward in 1935 to a new terminus at Corydon, where it ended at PA 159, a north–south route assigned in 1928 that began at PA 59 in Cornplanter and followed the Allegheny River north to the New York state line. This 10-mile (16 km) alignment of PA 159 remained in place until 1946, when all of PA 159 south of Corydon was replaced by an extended PA 346. The short segment of PA 159 between Corydon and the state line became unnumbered.

When the Allegheny Reservoir was completed in 1967, the portion of PA 346 near the Allegheny River was permanently inundated. As a result, PA 346 was rerouted slightly on its existing western end to head northwest to the state line, where it connected to the rebuilt New York State Route 280. Originally, PA 346 followed East Main Street in Bradford and Foster Brook. When the Bradford Bypass (US 219) was finished in 1977, the Pennsylvania Department of Transportation realigned PA 346 onto the bypass as well.