"I Should've Known" is a song by American singer-songwriter Aimee Mann, which was released in 1993 as the lead single from her debut studio album Whatever. The song was written by Mann and produced by Jon Brion. "I Should've Known" reached No. 55 in the UK Singles Chart and No. 16 in the US Billboard Modern Rock Tracks chart. In 1994, the single was reissued in the UK and Europe, and peaked at No. 45 in the UK Singles Chart.
