"Goodbye" was met with positive reception by
music critics. Quentin Harrison from Albumism described it as "a touching ode to beginnings and endings inspired by Horner. As 1998 closed, the triumph of that single in the United Kingdom and abroad was proof positive that the power of the Spice Girls had not been diminished by Horner’s exit."
Stephen Thomas Erlewine from
AllMusic commented that the song was "actually a pretty good finale". Fraser McAlpine from BBC America said that "this is the song they wrote after Geri left, and is also, coincidentally, the last decent thing they ever did as a group". Tania Kraines from
BBC Music said "the heartbroken post-Geri 'Goodbye' provided the girls with their last really good single". Chuck Taylor from
Billboard called the song's melody "absolutely beautiful, in fact, one of the group's most memorable, with well-rounded harmonies". Another editor, Jason Lipshutz ranked it as the seventh of "The Top 8 Spice Girls Songs" list, based on the songs' performances on the Hot 100 chart, whilst also stating that "the pangs of sorrow resulting in the realization that the Spice Girls' pop reign had effectively ended makes "Goodbye" a bittersweet hit". During his review of the 2007 compilation
Greatest Hits, Nick Levine of
Digital Spy said, "Best of all is 'Goodbye', the supremely elegant ballad that became a post-Halliwell
Christmas number one". Sarah Davis from
Dotmusic website commented that the "feelgood" chorus was "strong enough for this otherwise unremarkable song to be lifted above ordinariness". British music magazine
NME said "Goodbye" was a fine song in any age. A review of
Sputnikmusic considered the song "very tasteful and emotionally sweeping". Whitney Matheson of
USA Today, whilst reviewing their last studio album
Forever, wondered, "who the heck ends their album with an old chart-topper? Is this — like the repeated mentions of
Carnie,
Wendy and
Chyna — a subliminal message? Are the Spice Girls simply playing a game, or are they perhaps saying goodbye to their fans?". ==Chart performance==