"Baby You Don't Wanna Know" is the second single from Sum 41's fifth studio album Screaming Bloody Murder, officially released as a Canadian radio single on June 15, 2011, and later worldwide, along with a music video, on August 3, 2011.

As confirmed on Sum 41's Screaming Bloody Murder making of documentary Don't Try This at Home, "Baby You Don't Wanna Know", along with "Time for You to Go", was one of the two songs that were written and recorded by the band at the last minute, on April 7, 2010, at EastWest Studios in Hollywood, California. The song, co-written by Matt Squire, was added to the album at the last minute and its recording was funded by Deryck Whibley himself, as the label refused to pay for any more songs for the album.

As said by Todd Morse on Don't Try This at Home, the song's style was more in the vein of classic rock and "straight-up-rock and roll", taking influence from the Rolling Stones and the Beatles, as opposed to all the other songs that were written during 2008–2009, that resulted in a more "dark" alternative rock style.

In an interview with the band during their European tour in July 2011, the band has commented that they considered releasing either "Blood in My Eyes" or "Back Where I Belong" as the second single, but opted to release "Baby You Don't Wanna Know" instead, as it was more radio friendly.

On June 28, 2011, Sum 41's Twitter has announced that the band shot a music video for "Baby You Don't Wanna Know" during a day off in Germany, to be released in the coming month. In July 2011, band assistant Matt Whibley has confirmed that the music video was shot with a local German crew and is low budget. On August 3, 2011, the band premiered the music video for the song exclusively on German website Myvideo.de. A day later, it premiered on VEVO and YouTube, for worldwide audiences.

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