<p><i>Capparis montis-aquae</i>, a new species from limestones of the Da Nang Province, Vietnam, is described and illustrated. The new species is an erect shrub, characterised by complete glabrescence of the vegetative and reproductive parts, the presence of cataphylls at the base of the twigs, stipular thorns straight, small or in some cases lacking, leaves coriaceous, elliptic or narrowly obovate, flowers in lateral or terminal, few-flowered racemes, petals large, white, ovary ribbed and a knob-shaped stigma. The new species is related to <i>C. brachybotrya</i>, a species from Indonesia, but <i>C. brachybotrya</i> differs in slightly recurved thorns, an acuminate leaf apex, up to 20-flowered racemes, puberulous pedicels, longer sepals, shorter petals, puberulous outside, more stamens and a smaller ovary. The affinities of the new species are discussed and its conservation status is provisionally assessed.</p>