Osojnik (pronounced [ɔˈsoːi̯nik]) is a settlement north of Semič in southeastern Slovenia.

The municipality is now included in the Southeast Slovenia Statistical Region.

[2] Osojnik was attested in written sources in 1477 as Ossoynigk and Ossenigkh (and in 1674 as Ossoinigkh).

The freeholder Janez Konda served as a judicial officer in Osojnik from 1727 to 1738.

On 4 July 1943, Italian troops burned nearly the entire village while withdrawing before a Partisan attack at Hom Hill.