Bač pri Materiji (pronounced [ˈbatʃ pɾi matɛˈɾiːji]) is a small settlement in the Municipality of Hrpelje-Kozina in the Littoral region of Slovenia.

[2] The settlement includes the hamlet of Gabrk half a kilometer southeast of the village core.

The name Bač is related to the Slovene common noun beč '(stone- or wood-lined) hollow with a spring' (< *bъťъ), referring to a local geographical feature.

The Slavic word *bъťъ was borrowed from Latin buttis 'barrel' and is also the origin of the Slovene toponyms Beč and Buč.

Štefak Cave (Slovene: Štefakova pečina) was used by locals as a shelter from Italian fascist troops.