Acianthera angustisepala is a species of epiphytic plant in the Orchidaceae family.
Acianthera angustisepala is native to southeastern Mexico (Chiapas), Belize, and Guatemala. It is an epiphyte found in forests at elevations of 800 to 1350 meters.
The species was first described Pleurothallis angustisepala in 1942. It was renamed Acianthera angustisepala by Alec Melton Pridgeon and Mark Wayne Chase in Lindleyana 16: 247 in 2001.