Noctua interjecta, the least yellow underwing, is a species of moth of the family Noctuidae.

Forewing greyish rufous, sometimes darkened with fuscous; lines and stigmata a little darker, often very obscure; hindwing orange yellow with a broad marginal black border; costal and inner margins, a submedian streak from base, and the cell blackish; fringe yellow.

[1][2] [3] The larva is pale ochreous with black dots; the lines pale, with darker edges.

In Belgium and the Netherlands, this species flies in one generation from late June to August.

The larvae feed on various grasses and herbaceous plants such as meadowsweet (Filipendula ulmaria) and common mallow (Malva sylvestris).