In contribution to the All Taxa Biodiversity Inventory, a survey of the subfamily Phasiinae (Diptera: Tachinidae) was conducted in Great Smoky Mountains National Park. Phasiines are brightly colored endoparasitoid flies that primarily attack true bugs (Heteroptera) and can be important pollinators in meadow habitats. Collections were made from August to October over a two-year period at two sites: Purchase Knob in Haywood Co., North Carolina in 2013 and Cades Cove in Blount Co., Tennessee in 2014. Phasiines were collected by sweep net and Malaise traps (baited with host pheromone lures and unbaited). Species identifications were made using updated morphological keys, comparisons to identified specimens in collections, and sequence comparisons to known species using the nuclear coding gene MCS. In total, 221 specimens representing 27 tachinid species were collected. Of these, 21 species are newly recorded from the GSMNP, five are new records for Tennessee, and four are new records for North Carolina. All 12 eastern Nearctic phasiine genera were represented. Phasiines of the genus Gymnoclytia were shown to be exceptionally attracted to pheromones of the brown stink bug (Euschistus spp.).