Aristotelia themerastis is a moth of the family Gelechiidae.

It is found in Australia, where it has been recorded from New South Wales.

The forewings are pale-grey irrorated with darker grey and with four fuscous discal dots, often partly obsolete, the first at one-third, the second on the fold obliquely beyond the first, the third at two-thirds and the fourth beneath and beyond the third.

There is a slight blackish irroration at the apex and along the termen.

This article on a moth of the genus Aristotelia is a stub.