Amastra flavescens is a species of land snail, a terrestrial pulmonate gastropod mollusc in the family Amastridae.
The length of the shell attains 14.8 mm.
(Original description) The shell is dextral and conical, composed of six slightly rounded whorls with a simple, well-impressed suture. The surface is adorned with numerous, well-developed longitudinal striations. The aperture is semi-ovate, with a simple lip, and the short columella features an oblique plaited tooth.
Externally, the shell displays a uniform light reddish-yellow coloration, while the interior is either white or pale rose.
This marine species is endemic to Hawaii.