Sonchus congestus is a species of flowering plant in the family Asteraceae. It is endemic to the Canary Islands (Gran Canaria and Tenerife).
Sonchus congestus is a shrub up to tall. The leaves form a rosette at the ends of the stems. The leaves are relatively smooth (subglabrous), and have triangular to rounded lobes along their length. The flower heads are large, up to across.
Sonchus congestus is endemic to the Canary Islands. In Tenerife, it is found in forested areas in Sierra Anaga and along the north coast at elevations of . It is also found in the central and northern regions of Gran Canaria.