A new species, Phyllanthus mutisianus, is described on the basis of a collection from Colombia made by the expedition of José Mutis. It is distinguishable from all other neotropical species of Phyllanthus by virtue of the distinctive leaf venation and very long fruiting pedicels. The type specimen lacks mature flowers, but the vegetative morphology, inflorescence, and fruiting structures suggest placement in subgenus Xylophylla, section Elutanthos.