List of Billboard Hot 100 number ones of 1978

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 1978, 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, 20 different singles spent time at number one.^[2]

In the issue of Billboard dated January 7, the number-one single was "How Deep Is Your Love" by the Bee Gees, the song's third week in the top spot.^[3] A week later, it was displaced by "Baby Come Back" by Player, but in the issue dated February 4, the Bee Gees returned to the top spot with "Stayin' Alive", which held the number-one position for four weeks; it was the first of four consecutive chart-toppers to be written, either wholly or in collaboration, by Barry Gibb, one of the three brothers that comprised the group.^[4] "Stayin' Alive" was displaced from the top spot by "(Love Is) Thicker Than Water" by Andy Gibb, the younger brother of the Bee Gees;^[5] his siblings returned to number one in the issue of Billboard dated March 18 with "Night Fever", which topped the chart for eight consecutive weeks, the year's longest run atop the Hot 100. It meant that the four Gibb brothers had between them topped the chart for 14 consecutive weeks. "If I Can't Have You" by Yvonne Elliman was the fourth consecutive chart-topper (and the fifth of the year to date) to include Barry Gibb among its writers when it spent a single week at number one in the issue dated May 13; Gibb thus broke a record held by John Lennon and Paul McCartney of the Beatles, who had written three consecutive number ones in 1964.^[6] "How Deep Is Your Love", "Stayin' Alive", "Night Fever", and "If I Can't Have You" were all taken from the soundtrack of the film Saturday Night Fever.^[7]

The chart dominance of the Gibb brothers continued in June and July, when Andy spent seven weeks at number one with "Shadow Dancing". He and his older brothers, who co-wrote "Shadow Dancing" with him,^[8] were the only two acts with multiple chart-toppers during the year. The Bee Gees had the highest total number of weeks in the top spot in 1978 with 13, and Andy Gibb had the second-highest total with 9. "Grease" by Frankie Valli was the seventh Barry Gibb-penned number one of 1978 when it topped the chart for two weeks in August and September.^[9] Valli's song was the second number one from the soundtrack of the film Grease following "You're the One That I Want" by its stars John Travolta and Olivia Newton-John.^[10] During the year, 12 acts reached number one on the Hot 100 for the first time. Player, Elliman, Travolta, Deniece Williams, Commodores, A Taste of Honey, Exile, Nick Gilder, Anne Murray, Donna Summer, and Chic all gained the first pop number ones of their careers.^[11] Johnny Mathis's collaboration with Williams on "Too Much, Too Little, Too Late" gave him his first number one since Billboard combined their previously separate sales and airplay charts to create the Hot 100 in 1958; his last pop chart-topper had been on the Most Played by Jockeys listing in 1957.^[12]