Sestra flexata, also known as the common fern looper, is a species of moth in the family Geometridae.

[2] George Hudson discussed and illustrated this species in his 1928 book The butterflies and moths of New Zealand.

[7] The larvae are approximately 1 to 1+1⁄4 inch long and is a brownish greenish colour with yellow tones underneath.

Forewings acute, subfalcate, with a blackish shade on nearly half the middle space and along the exterior border, which is distinctly angular.

Hind wings yellowish, without markings; fore part of the exterior border slightly truncated.

[1] This species is found throughout New Zealand including the North, South, Stewart and Chatham Islands.