"I Will Always Love You" is a song written by American singer-songwriter Dolly Parton in 1973, who first released the song as a single in 1974. American singer Whitney Houston's (1992) version of the song became one of the best-selling singles of all time.

Dolly Parton wrote the song in 1973 and it was released a year later, having been produced by Bob Ferguson. She has told numerous interviewers over the years that she wrote it for her one-time partner and mentor Porter Wagoner, with whom she was having a business splitting at the time. Recorded on June 17, 1973, in RCA's Studio "B" in Nashville, the song was included on Parton's album Jolene, and was released as a follow-up single, after the country chart-topping success of the title track, in April 1974. The single reached number 1 on the Billboard Hot Country Songs a month later, but had just modest success on the pop charts. The lyrics express a bittersweet and poignant ode to an ex-lover, and are delivered with Parton's distinctive twang.

Parton re-recorded the song in 1982 to include it on the soundtrack of The Best Little Whorehouse in Texas, the film version of the Broadway musical of the same name. Her 1982 version also reached number 1 on the U.S. Hot Country Songs, marking the first time the same song reached number 1 on the country charts twice by the same artist. The 1982 version also saw limited crossover pop success, reaching number 53 on the Billboard Hot 100 and number 17 on the Hot Adult Contemporary Tracks.

Parton had success with the song again in 1995 in a duet with Vince Gill. This time the song peaked at number 15 in December of that year, making it the third time the song was a hit for Parton, albeit in duet form this time. In 2003, CMT ranked it number 16 on their 100 Greatest Songs in Country Music. A year later, CMT ranked it number 1 on their 100 Greatest Country Love Songs.

The most recent release of the song appears on Parton's 2008 album Backwoods Barbie, which features a live version - an exclusive iTunes bonus track.

In 1992, singer Whitney Houston recorded the song for the soundtrack to The Bodyguard, her film debut. Houston was originally to record Jimmy Ruffin's "What Becomes of the Brokenhearted" as the lead single from The Bodyguard. However, when it was discovered the song was to be used for Fried Green Tomatoes, Houston requested a different song and her co-star Kevin Costner brought her Linda Ronstadt's 1975 version of "I Will Always Love You" from her album Prisoner in Disguise. Houston and producer David Foster re-arranged the song as a soul ballad. Her record company did not feel a song with an a cappella introduction would be as successful; however, Houston and Costner insisted on retaining the a cappella intro. The tenor saxophone solo was played by Kirk Whalum. Whitney Houston's recording is not the only version of the song featured in the movie. In a scene where she dances with Kevin Costner, a version by John Doe can be heard playing on a jukebox.

Houston's version was a massive worldwide success, selling over 12 million copies worldwide. It became a regular on countdown lists: appearing at number 8 on VH1's 100 Greatest Songs of the Past 25 Years; number 4 on VH1's 100 Greatest Songs of the 90s and number 1 on VH1's 100 Greatest Love Songs. The song also lists at number 68 on Billboard's Greatest Songs of all time.

The single's music video, credited to Alan Smithee, begins with the performance of the song Houston gives at the end of The Bodyguard. The video then cuts to Houston in a dark blue suit sitting in an empty theater with the spotlight shining on her, singing of her love. The video is intercut with scenes from The Bodyguard and gives the viewer the experience of reliving the moments with the singer. She is also filmed sitting during this video due to her pregnancy with her daughter.

The single spent fourteen weeks at the top of the U.S. Billboard Hot 100, which at the time was a record. The single became Houston's longest run at number 1, beating her previous record of three weeks with 1986's, "Greatest Love of All." It is also the longest running number 1 single from a soundtrack album.

The single debuted at number 40 on the Billboard Hot 100 and became Houston's tenth number 1 hit a mere two weeks later. It also dominated various other Billboard charts, spending fourteen weeks at the top of Billboard Hot 100 Single Sales (the most for a solo female artist & later tied by Mariah Carey's We Belong Together), and eleven weeks at number 1 on its Hot 100 Airplay. The song also stayed at number 1 for five weeks on the Hot Adult Contemporary Tracks and for eleven weeks on the Hot R&B/Hip-Hop Songs becoming the longest running number 1 on the R&B charts at the time, and remained in the top 40 for twenty-four weeks. It became Arista Records' biggest hit. The song was number 1 on the Hot 100, Adult Contemporary, and R&B chart simulateously for a record five weeks.