"Who Did You Think I Was" is the debut single by blues-rock group John Mayer Trio from their first album, Try!. As it is from a live album, the single itself is a live recording. Speculation that Mayer was moving away from his known field of sensitive acoustic pop rock into blues was confirmed by the release of this single, being that it's a moderately heavy blues-rock song. Furthermore, the line from the first verse, "Got a brand new blues that I can't explain", indicates Mayer exploring blues unlike before.

The song also appeared as the B-side on the Trio's subsequent EP, "Live @ Yahoo! Music", after the track, "Out of My Mind", a heavily blues-influenced song written by Mayer which also appears on Try!.

The B-side to "Who Did You Think I Was" is "Come When I Call", which did not appear on the album Try!, but was frequently played throughout the trio live performances, like the song, "I Don't Need No Doctor".