List of Billboard Hot 100 number ones of 1977

The Billboard Hot 100 is a chart published since August 1958 by Billboard magazine which ranks the best-performing singles in the United States.^[1] In 1977, it was compiled based on a combination of sales and airplay data sourced from surveys of retail outlets and playlists submitted by radio stations respectively.^[1] During the year, 29 different singles spent time at number one.^[2]

The first issue of Billboard with a 1977 cover date was dated January 8, as the magazine published a special double issue dated December 25, 1976, and did not release an issue the following week.^[3] For the first time in the Hot 100's history, the chart was not updated that week, and every entry on the Hot 100 was "frozen" in position from the previous week.^[4] This included the number one for the final week of 1976, Rod Stewart's "Tonight's the Night (Gonna Be Alright)", which received an eighth week at number one as a result of the frozen chart.^[5] In the issue dated January 8, it was displaced by "You Don't Have to Be a Star (To Be in My Show)" by Marilyn McCoo and Billy Davis Jr.; the married singers had achieved two number ones in the 1960s as part of the 5th Dimension but it was their first chart-topper as a duo.^[6] Leo Sayer, Rose Royce, Mary MacGregor, and Manfred Mann's Earth Band all also topped the Hot 100 for the first time in January and February.^[7] Sayer returned to the top spot in May with "When I Need You" and was one of only three acts with two number ones in 1977, along with Stevie Wonder and the Eagles. Manfred Mann's Earth Band's "Blinded by the Light" was a cover version of a song written and originally recorded by Bruce Springsteen;^[8] although he is one of the most successful recording artists of all time,^[9] none of Springsteen's own singles have topped the Hot 100.^[8] Between March and June, Daryl Hall and John Oates, ABBA, David Soul, Thelma Houston, and Fleetwood Mac all reached number one for the first time.^[10] ABBA is also one of the commercially successful acts of all time worldwide,^[11] but the single week which the Swedish group spent atop the chart with "Dancing Queen" was its only appearance at number one in the United States.^[12]

In October, Debby Boone gained her first number one with "You Light Up My Life".^[13] The single occupied the top spot for ten consecutive weeks, setting new records for both the longest unbroken run and the highest total number of weeks spent by a single atop the Hot 100; previously singles by Bobby Darin, Percy Faith, and the Beatles had spent nine weeks in the top spot, either consecutively or non-consecutively.^[14] "You Light Up My Life" appeared in the film of the same name, released earlier the same year, in which it was performed by Kasey Cisyk,^[15] but Joseph Brooks, who produced and scored the film, was dissatisfied with her performance and brought Boone in to record a version for release as a single.^[15] Cisyk's version was subsequently also released but only reached number 80.^[16] Boone's single was one of several number ones of 1977 which were either taken directly from films or were re-recordings of themes from recent films. Rose Royce's "Car Wash" appeared in the film of the same name and Barbra Streisand reached number one with "Evergreen (Love Theme from A Star Is Born)", from A Star is Born, in which she starred.^[17] Bill Conti gained his first and only number one in July with "Gonna Fly Now (Theme From Rocky)", taken from Rocky, and Meco did the same in October with a disco-style recording of themes from Star Wars.^[18] The year's final chart-topper was "How Deep Is Your Love" by the Bee Gees, which was featured in the disco-themed film Saturday Night Fever.^[19] Andy Gibb, the younger brother of the Bee Gees, gained his first number one in the second half of the year, as did Alan O'Day, Shaun Cassidy, and the Emotions.^[20]