Sidironero (before 1927: Osenitsa, Осеница) is a village and a former community in the Drama regional unit, East Macedonia and Thrace, Greece. Since the 2011 local government reform it is part of the municipality Drama, of which it is a municipal unit. It lies in the Rhodope Mountains region along the Bulgarian border in the northern part of the Drama regional unit between Kato Nevrokopi and Paranesti. Its land area is 351.273 km2 (135.627 sq mi).
The municipal unit is subdivided into two local communities (constituent villages listed in brackets):