"Wedding Bell Blues" is a song written and recorded by Laura Nyro in 1966 that became a number one hit for The 5th Dimension in 1969 and subsequently a popular phrase in American culture. The song is written from the perspective of a woman whose boyfriend has not yet proposed to her, who wonders, "am I ever gonna see my wedding day?" The song carries dual themes of adoring love and frustrated lament.

Nyro wrote "Wedding Bell Blues" at the age of 18 as in effect a "mini-suite," featuring several dramatic rhythmic changes — a trait Nyro expanded on future albums. It was to be recorded in 1966 for Verve Folkways label as part of what would become her More Than a New Discoveryalbum. However, producer Herb Bernstein did not allow Nyro to record this version, which led to Nyro more or less disowning the entire album.

What was recorded was fairly similar in content and arrangement to the later, much more familiar 5th Dimension version, albeit with a somewhat more soulful vocal line. It was released as a single in September 1966 and remained on the Billboard Pop Singles "Bubbling Under" charts segment for several weeks, peaking at #103.

The 5th Dimension had already found hits with Nyro's "Stoned Soul Picnic" and "Sweet Blindness" during 1968. When recording tracks for their upcoming album The Age of Aquarius, producer Bones Howe suggested it would be amusing to record another Nyro song, this one about a woman trying to get someone named Bill to commit to marriage. As it happened, 5th Dimension singer Marilyn McCoo was engaged to another member, Billy Davis, Jr., though they had not set a wedding date. So the group recorded it, and in May 1969 the album was released. The first single ahead of the album, "Aquarius/Let the Sunshine In", was a tremendous hit, while success of the second single, "Workin' On a Groovy Thing", was much more moderate. Then a disc jockey in San Diego began playing "Wedding Bell Blues" off the album, Soul City Records saw its potential, and in October 1969 it was put out as a single.

"Wedding Bell Blues" quickly soared to number one on the U.S. pop singles chart, spending three weeks there in November, 1969. It also reached the top spot on the U.S. adult contemporary chart, made one of the group's somewhat rare appearances on the U.S. R&B singles chart, was a Top Five hit in Canada, and placed in the Top 20 on the UK Singles Chart (and their only hit there save for the earlier "Aquarius/Let the Sunshine In").

In 1969 television appearances, McCoo would explicitly sing parts of the song to Davis; Davis would respond with quizzical looks. (As it happens, they would indeed marry in 1969.) The rest of The 5th Dimension's early hits featured more unison singing than this, and McCoo's prominent vocal and stage role on "Wedding Bell Blues" may have led to her being more featured in the group's early 1970s productions.

Lesley Gore recorded her own version of the song for Mercury Records; this version was released in September 1969, and failed to chart, overwhelmed by the attention given to The 5th Dimension's recording.

The phrase "wedding bell blues" soon became cultural shorthand for anyone in doubt about the subject event or the state of being unmarried in general. As such many written or dramatic works have been named after the song title. These include:

The song also features on 'Being There', a Series One episode of Ally McBeal, during one of Ally's 'fantasy sequences' in the law firm office. The song is here sung by Vonda Shepard.

The song was also used in a scene with an erotic dancing hologram in the 1993 television mini-series Wild Palms.

The song was parodied in the second episode of the thirteenth season of The Simpsons, The Parent Rap. Homer sings incorrect lyrics to the song over the radio, and the radio station deejay says that the song was "Weddings are Nice" by the 5th Dimension.