Rudbeckia triloba, the browneyed or brown-eyed susan, thin-leaved coneflower or three-leaved coneflower,is a species of flowering plant in the daisy family Asteraceae, native to the United States. It is often seen in old fields or along roadsides. It is also cultivated as an ornamental.

It is a short-lived herbaceous perennial found in the Central and Eastern United States. Height is 2–3 ft (60–90 cm) with a spread of 1.0 to 1.5 ft (30 to 45 cm). The species requires full sun and moist soil. It is easy to grow. Spent flowers should be removed to encourage additional bloom, prevent any unwanted self-seeding, or both. This species usually has smaller flowerheads, more flowerheads per plant, and fewer ray flowers per flowerhead than Rudbeckia hirta. Rudbeckia triloba basal leaves are often trifoliate (three leaflets, sometimes each of the three also divided).