"Didn't Know I Had It" is a song by American rock band Cheap Trick, released in 1994 as the fifth and final single from their twelfth studio album Woke Up with a Monster.

On YouTube, two audience recorded videos exist of the band performing the song live; one on July 17, 2010, at Meadowbrook Pavilion, Gilford, New Hampshire[8] and the other on September 30, 2011, at The Big E in West Springfield, Massachusetts.

[9] In a review of Woke up with a Monster, Dave Connolly of AllMusic said: "...if their power pop is a little over the top, underneath are some very good songs: "Didn't Know I Had It," "Tell Me Everything," "You're All I Wanna Do."

"[11] In his 2017 book Still Competition: The Listener's Guide to Cheap Trick, Robert Lawson described the song as having a "determined lead vocal and some acoustic guitar in the mix".

"[13] In another review of one of the band's 1994 concerts, Troy J. Augusto of Variety commented: "A couple of songs, notably tear-jerker "The Flame" and new dud "Didn't Know I Had It," will quickly be forgotten.