Syens is a municipality in the district of Broye-Vully in the canton of Vaud in Switzerland .

Syens is first mentioned in 1018 as Ciens.

Syens has an area, as of 2009, of 2.5 square kilometers (0.97 sq mi). Of this area, 1.39 km2 (0.54 sq mi) or 55.2% is used for agricultural purposes, while 0.84 km2 (0.32 sq mi) or 33.3% is forested. Of the rest of the land, 0.28 km2 (0.11 sq mi) or 11.1% is settled (buildings or roads).

Of the built up area, housing and buildings made up 3.2% and transportation infrastructure made up 7.1%.