A new species of the poorly known mygalomorph genus Strophaeus Ausserer, 1875 is described. The new species, Strophaeus quillacinga sp. nov., is described from Nariño, Colombia. It represents the first record of Strophaeus from Colombia, with the genus previously only known from Peru, Brazil, and Panama. This species can be distinguished from other known female congeners by the presence of a higher number of spines on the rastellum and the abdomen dorsally mottled.