Buddleja alternifolia, known as alternate-leaved butterfly-bush,[1] is a species of flowering plant in the figwort family, which is endemic to Gansu, China.

A substantial deciduous shrub growing to 4 metres (13 ft) tall and wide, it bears grey-green leaves and graceful pendent racemes of scented lilac flowers in summer.

The inflorescences of the plants in cultivation are bright lilac-purple, and comprise flowers so densely crowded in clusters along the branch as to often obscure it.

In his 1979 revision of the taxonomy of the African and Asiatic species of Buddleja, the Dutch botanist Anthonius Leeuwenberg sank two species, B. legendrei and B. tsetangensis, as B. alternifolia on the basis of the similarity in the individual flowers, dismissing the variations in plant structure, flower colour and leaf as attributable to environmental factors.

Fully hardy, it prefers a sunny position and loamy soil; pruning should immediately follow flowering.