The species is sexually dimorphic: the female is a yellow-green and the male a turquoise blue with a small deep black face and upper throat patch.

The swallow tanager was formally described in 1811 by the German zoologist Johann Karl Wilhelm Illiger under the binomial name Hirundo viridis.

[3] The species is now the only member of the genus Tersina that was introduced in 1819 by the French ornithologist Louis Pierre Vieillot.

[4][5] The genus name is from the French Tersine, an unidentified bird described by Georges-Louis Leclerc, Comte de Buffon.

[7] Three subspecies are recognised:[5] The swallow tanager is 14.5–15 cm (5.7–5.9 in) in length with a broad flat bill.