Santena is a comune in the Metropolitan City of Turin in the Italian region Piedmont, located about 15 kilometres southeast of Turin on the right bank of the Po. The frazione of Gamenario is known for the Battle of Gamenario, fought on 22 April 1345 between the Guelphs and Ghibellines. Sights include the castle, built by Carlo Ottavio Benso in 1712–20.