Geomalacus oliveirae is a species of air-breathing land slug, a terrestrial pulmonate gastropod mollusc in the family Arionidae, the round back slugs.

Distribution of Geomalacus oliveirae include: Geomalacus oliveirae is a slug light with 4 black colour bands, inner bands are irregularly interrupted, main marginal bands sharply delimited against the light background.

[2] Reproductive system: Genital retractor inserts more anteriorly in the median line of dorsum than in the other species.

[2] Geomalacus oliveirae lives in Portugal in Mediterranean shrubland and on granitic substrate, also under Betula, Pinus and Juniperus trees, below 1300 m.[2] It lives in Spain under Pinus and in olive orchards.

[2] This article incorporates public domain text from the reference.