The wingspan of Pyrgus onopordi can reach 22–28 mm. The upper side of the frontwings and hindwings is dark brown or khaki with a slight yellowish tinge, white markings, and a white fringe on the edge. The underside hindwings is light yellow-brown marbled with a few large white spots, including a characteristic anvil-shaped discal mark bordered with dark lines in the cells four and five.
The wingspan of Pyrgus onopordi can extend from 22–28 mm. The upper side of the frontwings and hindwings is dark brown or khaki with a slight yellowish tint, white markings, and a white border along the edge. The underside hindwings is light yellow-brown marbled with several large white spots, including a distinctive anvil-shaped central mark framed by dark lines in cells four and five.