Phalaenopsis tetraspis is a species of epiphytic orchid endemic to the Andaman Islands, the Nicobar Islands and northwestern Sumatra. It was originally erroneously published as a Himalayan species by Reichenbach, which was corrected by James Veitch 23 years after Heinrich Gustav Reichenbachs publication.
Mature specimens may have up to nine leaves, but usually plants have 4–5, elliptic-obovate, acute to obtuse, 20 cm long and 8 cm wide leaves. Showy, fleshy, fragrant flowers are produced on axillary, arching to subpendent racemes or panicles. A prominent feature of this species is the midlobe of the labellum, which is oblong, obtuse-subacute, and the apex is covered in dense trichomes. The karyotype is asymmetric and nonuniform.