The genus name Gladiolus comes from the Latin word gladius, meaning sword, and refers to the shape of the leaves of all members of the genus. The species name oppositiflorus refers to the opposite-facing flowers, but this is not a unique characteristic to this species, as some closely related species such as G. elliotii and G. sericeovillosus also have opposite-facing flowers.

The species was first mentioned in horticultural literature in 1837 by the Rev. William Herbert (1778-1847), theologian, linguist, poet, amateur botanist and father of the English novelist Henry William Herbert. Herbert experimented with breeding garden hybrids from wild species of Gladiolus. The salmon-pink variety of this species is found further inland on the lower slopes of the Drakensberg, and is somewhat shorter-stemmed than the coastal form, the flowers do not open as widely and the inland variety is always deciduous whereas the coastal form is often evergreen. They were long thought to be two different species, or subspecies, with the salmon-pink variety called G. salmoneus by J.G Baker (1896). A.A. Obermeyer (Lewis et al . 1972) classified it as G. oppositiflorus subsp. salmoneus in her revision of the genus. Therefore, in many older gardening publications the two forms are referred to by separate common names, with the coastal form called Transkei gladiolus, whereas the salmon-pink, inland form is called salmon gladiolus. Goldblatt & Manning (1998) found that the two forms integrate in the central Eastern Cape and therefore they are currently considered to be a single species.