Ennomos quercinaria, the August thorn, is a moth of the family Geometridae.

The forewings are lightly or heavily speckled and have a dark marginal edge.

Both forewings and hindwings are scalloped at the edges and have two cross lines.

It is found in some but not all of western Europe, Belgium, The Netherlands, the Iberian Peninsula and to the east in Greece, Hungary, Romania, European Turkey, Ukraine and to the south, the Iberian Peninsula, Italy and Sicily.

The moths fly in one generation from August to September.