Wahlenbergia roxburghii, the Roxburgh bellflower or dwarf cabbage tree, is an extinct member of a group of four species of Wahlenbergia once known from the island of Saint Helena, in the South Atlantic Ocean.

William Roxburgh recorded it in the thick forests on the south face of Diana's Peak.

De Candolle notes it in dense woods around Diana's Peak and Halley's Mount.

It was probably the increase of Phormium tenax planting on the ridge that pushed Wahlenbergia roxburghii into final extinction.

It is an example of one of the early extinctions of Saint Helena plants as a result of human activity, with a history similar to that of the stringwood (Acalypha rubrinervis), (see List of extinct plants).