Osilnica (pronounced [ɔˈsiːu̯nitsa], in older sources also Osivnica,[2] German: Ossiunitz[2][3]) is a settlement in southern Slovenia.

It is located on the left bank of the Kolpa River next to the border with Croatia.

Osilnica was attested in historical sources in 1365 as Ossiwniz (and as Ossawnitz in 1456–61 and Ossynnitz in 1498).

Derivation from *osьlьnica (< *osьlъ 'donkey' or *osьla 'whetstone') has also been proposed, but is less convincing for vocalic reasons.

[6] The parish church in Osilnica is dedicated to Saints Peter and Paul and belongs to the Roman Catholic Diocese of Novo Mesto.