No One Can Ever Know is the third studio album by Scottish indie rock band The Twilight Sad, released by FatCat Records on 6 February 2012 in the UK, and a day later in the US. The album was produced by the band with assistance and advice from producer Andrew Weatherall, who helped the band in experimenting with analog synthesizers. No One Can Ever Know marks a shift in the band's "wall of sound" approach towards a darker, more industrial-influenced sound. Guitarist Andy MacFarlane describes the album's sound as "sparser... with a colder, slightly militant feel," influenced by artists such as Siouxsie and the Banshees, Can, Public Image Ltd, Fad Gadget, Cabaret Voltaire, Wire, Bauhaus, Magazine and D.A.F.

The album follows over two years since their previous full-length Forget the Night Ahead in September 2009, and the EP release The Wrong Car in September 2010. The band released a new song, the album's closing track "Kill It in the Morning", for free on their new website and SoundCloud page on 21 September 2011. The first proper single from the album, "Sick", was made available as a 7" vinyl single and digital download on 14 November 2011. The album's second single, "Another Bed", followed the album on 20 February 2012 as a limited edition, hand-stamped and numbered 7" single (limited to 200 copies) and digital download. Although the song was not released as a single, a music video was produced for "Dead City", directed by frequent collaborator Nicola Collins, and premiered online in April 2012.

The album also yielded two companion releases: No One Can Ever Know: The Remixes, featuring remixes from Liars, Com Truise, and Tom Furse from The Horrors; and N/O/C/E/K Tour EP, a limited release featuring alternate and demo recordings. In 2020, the original vinyl LP, after long being out of print, was repressed as a burgundy-coloured limited edition.