Parkia nana D. A. Neill (Leguminosae, Mimosoideae) from sandstone areas near the Río Marañón area in northeastern Peru is described and illustrated. Photographic evidence also indicates presence of this species on sandstone substrate in the Cordillera Azul in east-central Peru. Compared to other species of Parkia R. Brown, which commonly attain 30–40 m in height, P. nana has a dwarf growth form, found as a pachycaul treelet attaining reproductive maturity at 3–4 m in height. The new species is placed in the pantropical section Parkia R. Brown and is similar to P. nitida Miquel and P. balslevii H. C. Hopkins, with which it shares the opposite to subopposite leaves, the biglobose capitula, and indehiscent strap-shaped pods, but differs from both in its short stature, erect compound inflorescence, and erect, velutinous fruits.