Cantuaria medialis is a species of trapdoor spider endemic to New Zealand.

[1] This species was described in 1968 by Ray Forster from a single female specimen collected in Marlborough.

The carapace and legs are pale reddish to orange brown.

The abdomen is shaded dorsally with reddish brown.

[1] Under the New Zealand Threat Classification System, this species is listed as Data Deficient with the qualifiers of "Data Poor: Size", "Data Poor: Trend" and "One Location".