Mangua secunda is a species of Physoglenidae spider endemic to New Zealand.
This species was described in 1990 by Ray Forster from a female specimen. The holotype is stored in Otago Museum.
The female is recorded at 3.49mm in length.
This species is only known from Manawatu, New Zealand.
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".