Two subspecies currently are recognized (Zimmer 1943, Storer 1970, Hilty 2oo3):
xanthogastra (Sclater 1851); type locality "Rio Negro", restricted to Rio Negro [San Martín], Peru by Zimmer 1943.
Occupies most of the range of the species. See Detailed Description.
phelpsi Zimmer 1943; type locality Mt. Auyan-tepui, Venezuela, 1100 m. Type in the American Museum of Natural History, New York.
Similar to nominate xanthogastra, but "with longer wing and tail, heavier bill, more yellowish anterior under parts, more broadly yellow belly, duller flanks, more yellowish green head, and more metallic luster on the outer surface of the wings" (Zimmer 1943). This subspecies is restricted to the tepui mountains of southern Venezuela in Bolívar and Amazonas, and in adjacent Brazil (Mount Uei-tepui) (Storer 1970, Hilty 2003). The distribution of phelpsi overlaps geographically with that of xanthogastra, but the two are separated elevationally, with xanthogastra below 750 m and phelpsi at ca 1000-1800 m (Hilty 2003).
Yellow-bellied Tanager is classified in the genus Tangara, the largest genus of Neotropical birds. Tangara is divided into 13 species groups based on vocalizations, diet, geographic distributions, behavior, and appearance (Isler and Isler 1987). Of these 13 species groups, Yellow-bellied Tanager is a member of Group 6, which also includes Tangara guttata (Speckled Tanager), Tangara punctata (Spotted Tanager), Tangara varia (Dotted Tanager), and Tangara rufigula (Rufous-throated Tanager). These species are brightly colored, have a speckled appearance, and occur primarily in the canopy (Isler and Isler 1987). The monophyly of this group has been confirmed with mtDNA sequence data (Burns and Naoki 2004, Sedano and Burns 2010). Of the species in group 6, Tangara xanthogastra is most closely related to Tangara guttata (Burns and Naoki 2004, Sedano and Burns 2010).
The two subspecies of Yellow-bellied Tanager overlap geographically, in part, but are separated by elevation; Hilty (2003) suggested that "possibly" each taxon represents a distinct species.