Phytoecia nigricornis is a species of beetle in the family Cerambycidae. It was described by Johan Christian Fabricius in 1781, originally under the genus Saperda. It has a wide distribution throughout Europe. It measures between . It feeds on Glebionis segetum, Solidago virgaurea, Artemisia campestris, Artemisia absinthium, Artemisia vulgaris, Artemisia sieversiana, Leucanthemum vulgare, and Tanacetum vulgare.