Scoparia petrina is a species of moth in the family Crambidae. It was named by Edward Meyrick in 1884. Meyrick gave a description of the species in 1885. It is endemic to New Zealand.

The wingspan is 30–31 mm for males and 24 mm for females. The forewings are fuscous-grey or dark grey, irrorated with white. There is a very small dark fuscous triangular spot at the base of the costa. The first line is whitish, posteriorly margined with dark fuscous. The second line is whitish, anteriorly dark-margined and with blackish dots on the veins. The terminal area is somewhat irrorated with white, except for a broad suffused subterminal line. The hindwings are very pale whitish-ochreous with a greyish apex in females. Adults have been recorded on wing in January and February.

This species can be distinguished from others by the absence of black markings on its wings.

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