Socerb (pronounced [sɔˈtsɛːɾp] or [ˈsoːtsɛɾp]; in older sources also Sacerb, Italian: San Servolo)[2] is a village in the City Municipality of Koper in the Littoral region of Slovenia.

[3] It lies on the border with Italy and is dominated by the ruins of Socerb Castle, built on a rocky cliff above the village.

Socerb was attested in written sources in the 14th century as propre Sanctum Servulum (and in 1763–87 as St. Servolo).

The Slovene name is derived from *Sǫt-Serb: a combination of *sǫt- 'saint' (ultimately from Latin sanctus) plus *Serb (from Servu(lus), the name of a local saint, or from Servus, a 5th-century martyr in Thuburbo Majus).

The Socerb Cave behind Vrh Mass Grave (Slovene: Grobišče Socerbska jama za Vrhom) is located in the woods northeast of the village of Kastelec.