Plavnica (Hungarian: Palonca Плавніця) is a village and municipality in Stará Ľubovňa District in the Prešov Region of northern Slovakia.
In historical records the village was first mentioned in 1325. Before the establishment of independent Czechoslovakia in 1918, Plavnica was part of Sáros County within the Kingdom of Hungary. From 1939 to 1945, it was part of the Slovak Republic. On 23 January 1945, the Red Army dislodged the Wehrmacht from Plavnica and it was once again part of Czechoslovakia.
The municipality lies at an altitude of 530 metres and covers an area of 19.608 km2. It has a population of about 1544 people.