"If Only You Knew" is a single written and produced primarily by Dexter Wansel and Cynthia Biggs for American singer Patti LaBelle's sixth solo album, I'm in Love Again. It was released as the album's official first single in 1983, spending four weeks at #1 on the U.S. R&B chart during January and February 1984; it reached #46 on the Billboard Hot 100.[1]The most notable covers of the song were by jazz singer Phil Perry, who recorded it on his 1994 album, Pure Pleasure and Keke Wyatt, who recorded it on her debut solo album, Soul Sista. Wyatt said LaBelle called her to congratulate her on her recording of the song, saying humorously, "you better sing it, heffa". Singer-actress D'Atra Hicks also covered it for her album, Finally My Time and performed it in the Tyler Perry stage play What's Done in the Dark. Singer Oke also covered the song (in its Keke Wyatt-styled cover) in 2001, including the 90's Male Group Soul for Real.

R&B fictional quintet group Milestone sampled that riff as an interpolation for their track "I Care 'Bout You" from their Soul Food album. Chicago-based rap group Do or Die recorded an interpretative rap version with Twista and Syleena Johnson guest vocalizing on their album, D.O.D., as did Remy Ma on her mixtape, BlasRemy, as a dedication to then-boyfriend (now husband), Papoose. Remy's version sampled LaBelle's original. Another sample of the song came from Chicano rapper Capone, who had a song with the same name. Rapper Bizzy Bone included the sample of the song as an interpretation of his composition, "Nobody Can Stop Me", from his Heaven'z Movie album. In 2010, both Jasmine V and Ciara recorded the song "If Only", which interpolated parts of the LaBelle song. Jasmine's version was recorded as a demo while Ciara's version was deleted off the final track list of her album, Basic Instinct.

Other artists such as SWV (and group member Coko), Ledisi, Tamia, and Brian McKnight have covered the song in concert.

Rachelle Ferrell, Ron Isley, Peabo Bryson, and Tamia sang the song in tribute to LaBelle as she was honored at the 1998 Soul Train Music Awards.[2] Mariah Carey featured LaBelle's rendition of "Over the Rainbow" as part of her live tribute following a brief performance of "If Only You Knew" at the 1998 Essence Awards.[3]

SWV also included a cover on their 2012 album "I Missed Us", which went on to be nominated for Best Traditional R&B Performance at the 55th Annual Grammy Awards. SWV performed the song on the 22nd Annual Trumpet Awards in 2014 during the Gamble & Huff Tribute, other artists such as Joe, Carl Thomas, Lyfe Jennings, and the late Billy Paul was also part of that tribute. In 2015, Patti, Grammy-nominated singer Tamar Braxton, and R&B singer K. Michelle sang the song at the 15th annual BET Awards. R&B singer Tank sampled the song for his 2016 single "You Don't Know" featuring rapper Wale.