New York State Route 20SY (NY 20SY) was a state highway in the vicinity of Syracuse, New York, in the United States. It connected U.S. Route 20 (US 20) to downtown Syracuse via Skaneateles, Camillus, Manlius, and Cazenovia in Onondaga County and Madison County. The highway began at an intersection with US 20 and NY 321 in the village of Skaneateles and ended at a junction with US 20, NY 20N, and NY 92 near the village of Cazenovia. Most of NY 20SY overlapped another route; however, two sections of NY 20SY—one in the town of Camillus and another near the village of Fayetteville—were not concurrent with another highway.