Alyssum troodi is a 10–25 cm high perennial subshrub. Leaves 5–10 mm long obovate-spatulate, covered with a silvery indumentum. Flowering and sterile shoots on the same plant, On the sterile shots the leaves form terminal clusters. Flowers have 3 mm long golden-yellow petals. The siliques are 7–8 mm long, elliptic and glabrous. Flowers from May to July.