Metamynoglenes magna is a species of sheet weaver spider endemic to New Zealand.
This species was described in 1979 by A.D Blest from a female specimen. The holotype is stored in Otago Museum.
The female is recorded at 5.25mm in length. This species has a dark brown cephalothorax, dark brown legs and a grey abdomen that has white markings.
This species is only known from Nelson, New Zealand.
Under the New Zealand Threat Classification System, this species is listed as "Naturally Uncommon" with the qualifier of "Range Restricted".