On March 17, 2005, Kim was found guilty of conspiracy and perjury for lying to a grand jury about her friends' involvement in a 2001 shooting outside the Hot 97 studios in Manhattan. She claimed not to have known that her manager (Damion "D-Roc" Butler) and another friend (Suif Jackson) were at the scene, despite video footage showing all three exiting the building. Both men have pleaded guilty to gun charges since. In July 2005, she was sentenced to a one-year-and-a-day in the Philadelphia Detention Center. She had requested to go to a camp center in Connecticut to be closer to her mother, but instead was ordered to report to the Philadelphia Detention Center. Her lawyer stated that, "A year and a day is actually less than a year sentence, because according to federal sentencing guidelines, if there's an extra day, time is credited to you". A parole bill was filed that reduced her sentence. Throughout her entire jail sentence, Kim's representatives declared that she was busy working; she wrote over 200 songs while in prison.

Despite her conviction, Kim released a fourth album, The Naked Truth, during her sentence on September 27, 2005. It earned her a 5 mic rating from The Source, making her the only female rapper to ever accomplish this feat (two 5 mic ratings). The album debuted at #6 on the Billboard 200 charts, giving Kim her Third Top 10 debut on the charts. The Naked Truth didn't sell as well as her previous works, selling less than 400,000 copies. Kim has said that her jail sentence left her with no time to promote the project. There have been many rumors about a re-release of Truth but to no avail.

The music video for The Naked Truth's first single, "Lighters Up" was number one on BET's 106 & Park for two weeks. "Lighters Up", was a Top Ten hit on the Billboard Hot R&B/Hip-Hop Singles & Tracks chart. The single also reached #76 on the German Single Chart, #12 on the UK Top 75 and #4 on the Finland Single Chart. The second single, "Whoa" was released on February 17, 2006. It reached No. 22 on Airplay. On March 9, BET premiered the show Lil Kim: Countdown to Lockdown, which was filmed before Kim headed to jail. The show became the highest rated premiere in BET history, with 1.7 million viewers. In May 2006, Debbie Harry released a Lil' Kim tribute song called "Dirty and Deep" in protest of her conviction. The song is available free from the Deborah Harry Home Page. On June 6, 2006, Lil' Kim The Dance Remixes was released.

• Knocked Up (2007) (writer: "Lighters Up") (performer: "Lighters Up")
• King's Ransom (2005) (writer: "Magic Stick") (performer: "Magic Stick")
• The Girl Next Door (2004) (writer: "GET NAKED")
• You Got Served (2004) (writer: "Do That Thing") (performer: "Do That Thing")
• Grind (2003) (performer: "The Jump Off")
• 8 Mile (2002) (writer: "Player's Anthem") ("Get Money")
  ... aka 8 Mile (Germany)
  ... aka 8 Mile - Jeder Augenblick ist eine neue Chance (Germany: DVD box title)
• Ali G Indahouse (2002) (performer: "FRESH FROM YARD") ("FRESH FROM YARD")
  ... aka Ali G in da House (Germany) (UK: alternative spelling)
  ... aka Ali G (France)
  ... aka Ali G Indahouse: The Movie (Australia)
• All About the Benjamins (2002) (writer: "It's All About the Benjamins (Remix)")
  (performer: "It's All About the Benjamins (Remix)")
  ... aka All About the Money (Germany)
• Biggie and Tupac (2002) ("Play Around")
• "Paso adelante, Un" (1 episode, 2002)
       - Arriba el telón (2002) TV episode (performer: "Lady Marmalade")
• Dr. Dolittle 2 (2001) (writer: "Do U Wanna Roll (Dolittle Theme)")
  (performer: "Do U Wanna Roll (Dolittle Theme)")
  ... aka DR.2 (USA: promotional abbreviation)
  ... aka DR2 (USA: promotional abbreviation)
• Moulin Rouge! (2001) (performer: "ZIDLER'S RAP (Medley)")
• Un paso adelante. Historia de una serie (2001) (TV)
  (performer: "Lady Marmalade")