These are the Billboard magazine Hot 100 number one hits of 1978.
| Issue Date | Song | Artist(s) | Reference |
|---|---|---|---|
| January 7 | "How Deep Is Your Love" | Bee Gees | |
| January 14 | "Baby Come Back" | Player | |
| January 21 | |||
| January 28 | |||
| February 4 | "Stayin' Alive" | Bee Gees | |
| February 11 | |||
| February 18 | |||
| February 25 | |||
| March 4 | "(Love Is) Thicker Than Water" | Andy Gibb | |
| March 11 | |||
| March 18 | "Night Fever" | Bee Gees | |
| March 25 | |||
| April 1 | |||
| April 8 | |||
| April 15 | |||
| April 22 | |||
| April 29 | |||
| May 6 | |||
| May 13 | "If I Can't Have You" | Yvonne Elliman | |
| May 20 | "With a Little Luck" | Wings | |
| May 27 | |||
| June 3 | "Too Much, Too Little, Too Late" | Johnny Mathis and Deniece Williams | |
| June 10 | "You're the One That I Want" | John Travolta and Olivia Newton-John | |
| June 17 | "Shadow Dancing" | Andy Gibb | |
| June 24 | |||
| July 1 | |||
| July 8 | |||
| July 15 | |||
| July 22 | |||
| July 29 | |||
| August 5 | "Miss You" | The Rolling Stones | |
| August 12 | "Three Times a Lady" | Commodores | |
| August 19 | |||
| August 26 | "Grease" | Frankie Valli | |
| September 2 | |||
| September 9 | "Boogie Oogie Oogie" | A Taste of Honey | |
| September 16 | |||
| September 23 | |||
| September 30 | "Kiss You All Over" | Exile | |
| October 7 | |||
| October 14 | |||
| October 21 | |||
| October 28 | "Hot Child in the City" | Nick Gilder | |
| November 4 | "You Needed Me" | Anne Murray | |
| November 11 | "MacArthur Park" | Donna Summer | |
| November 18 | |||
| November 25 | |||
| December 2 | "You Don't Bring Me Flowers" | Barbra Streisand and Neil Diamond | |
| December 9 | "Le Freak" | Chic | |
| December 16 | "You Don't Bring Me Flowers" | Barbra Streisand and Neil Diamond | |
| December 23 | "Le Freak" | Chic | |
| December 30 |
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