Rudbeckia hirta (common names: Black-eyed Susan, Blackiehead, Brown Betty, Brown Daisy, Brown-eyed Susan (Rudbeckia triloba), Gloriosa Daisy, Golden Jerusalem, Poorland Daisy, Yellow Daisy, Yellow Ox-eye Daisy) is a flowering plant in the family Asteraceae. It is an upright annual (sometimes biennial or perennial) native to most of North America, and is one of a number of plants with the common name Black-eyed Susan with flowers having dark purplish brown centers.

The genus name honors Olaus Rudbeck, who was a professor of botany at the University of Uppsala in Sweden and was one of Linnaeus's teachers. The specific name refers to the trichomes (hairs) occurring on leaves and stems.

The plant can reach a height of 1 m. It has alternate, mostly basal leaves 10-18 cm long, covered by coarse hair. It flowers from June to August, with inflorescences measuring 5-8 cm in diameter (up to 15 cm in some cultivars), with yellow ray florets circling a brown, domed center of disc florets.

The Black-eyed Susan was designated the state flower of Maryland in 1918. Numerous cultivars have been selected for garden planting; some popular ones include 'Double Gold', 'Indian Summer', and 'Marmalade'.

The roots but not seedheads of Rudbeckia hirta can be used much like the related Echinacea purpurea. It is an astringent used as in a warm infusion as a wash for sores and swellings. The Ojibwa used it as a poultice for snake bites and to make an infusion for treating colds and worms in children. The plant is diuretic and was used by the Menominee and Potawatomi. Juice from the roots had been used as drops for earaches. The plant contains anthocyanins.