Astropanax myrianthus is a species of plant in the family Araliaceae.

It is a tree, shrub, or liana native to Madagascar[1] and the Comoro Islands.

[1] Astropanax myrianthus is found in the highlands of Madagascar's Anosy, Analamanga, Vakinankaratra, Diana, Sava, and Sofia regions (former Antananarivo, Antsiranana, Mahajanga and Toliara provinces).

The species' estimated extent of occurrence (EOO), calculated from 28 known collections, is 87,150 km2, and its minimum estimated area of occupancy (AOO) is 92 km2.

[1] At least 14 of the species' known subpopulations are threatened with habitat loss from shifting agriculture.