"Unforgivable Sinner" is a song written and performed by Norwegian singer-songwriter Lene Marlin, released as her debut single on 12 October 1998 from her first album, Playing My Game (1999).

Birmingham Evening Mail called the song a "mature" debut, describing it as the "sort of mid-tempo, intense material somebody like Natalie Imbruglia would release.

"[2] Håkon Moslet from Norwegian newspaper Dagbladet said in his review of Playing My Game, that "Unforgivable Sinner" is a "clear highlight" of the album.

[5] Pia M. Isaksen from Moss Dagblad was less enthustiastic, noting it as "traditional folk", adding that the melody is "nice".

[6] New Straits Times called it an "outstanding" tune "set to a pop-hiphop beat with a strong arrangement powered by acoustic guitars".

[7] Kjell Nordeng from Nordlands Framtid noted the song with "Sitting Down Here" as "cream of the crop" of the album.

"[11] Linda Nilsen from Tromsø gave the song 6 out of 6, noting that it is "simply something of the best I have ever heard from a Norwegian artist.

The second and international version of the video was directed by Stephen Scott and shot at a train station in Toronto, Canada.