Wallachia (Walachia, Valachia, Valahia) is a historical and geographical region of Romania.

Wallacia may refer to:

Wallacia, a trilobite genus, see Encrinuridae Wallacia, New South Wales, a suburb of Sydney in Australia Wallacia Mandi, a Mandaean temple under construction in Wallacia

See also Wallacea, a group of islands mainly in Indonesia Wallasea Island, an island in Essex, England