Nižná Sitnica is a village and municipality in Humenné District in the Prešov Region of north-east Slovakia.
In historical records the village was first mentioned in 1408.
The municipality lies at an altitude of 187 metres and covers an area of 9.172 km².
It has a population of about 370 people.
Coordinates: 49°04′N 21°48′E / 49.067°N 21.800°E / 49.067; 21.800