# List of Billboard Mainstream Top 40 number-one songs of 2017

This is a list of songs which reached number one on the Billboard Mainstream Top 40 (or Pop Songs) chart in 2017.
During 2017, a total of 18 singles hit number-one on the charts.

## Chart history

Key :
| † | Indicates best-performing single of 2017 |
| Issue date | Song | Artist(s) |
| January 7 | "Side to Side" | Ariana Grande featuring Nicki Minaj |
| January 14 | "Side to Side" | Ariana Grande featuring Nicki Minaj |
| January 21 | "Side to Side" | Ariana Grande featuring Nicki Minaj |
| January 28 | "Don't Wanna Know" | Maroon 5 featuring Kendrick Lamar |
| February 4 | "Scars to Your Beautiful" | Alessia Cara |
| February 11 | "Scars to Your Beautiful" | Alessia Cara |
| February 18 | "Bad Things" | Machine Gun Kelly and Camila Cabello |
| February 25 | "Bad Things" | Machine Gun Kelly and Camila Cabello |
| March 4 | "Shape of You" | Ed Sheeran |
| March 11 | "Shape of You" | Ed Sheeran |
| March 18 | "Shape of You" | Ed Sheeran |
| March 25 | "Shape of You" | Ed Sheeran |
| April 1 | "Shape of You" | Ed Sheeran |
| April 8 | "Shape of You" | Ed Sheeran |
| April 15 | "Shape of You" | Ed Sheeran |
| April 22 | "Shape of You" | Ed Sheeran |
| April 29 | "Shape of You" | Ed Sheeran |
| May 6 | "That's What I Like" | Bruno Mars |
| May 13 | "That's What I Like" | Bruno Mars |
| May 20 | "That's What I Like" | Bruno Mars |
| May 27 | "Something Just Like This" | The Chainsmokers and Coldplay |
| June 3 | "Something Just Like This" | The Chainsmokers and Coldplay |
| June 10 | "Stay" | Zedd and Alessia Cara |
| June 17 | "Stay" | Zedd and Alessia Cara |
| June 24 | "Stay" | Zedd and Alessia Cara |
| July 1 | "Stay" | Zedd and Alessia Cara |
| July 8 | "Stay" | Zedd and Alessia Cara |
| July 15 | "Stay" | Zedd and Alessia Cara |
| July 22 | "Despacito" | Luis Fonsi and Daddy Yankee featuring Justin Bieber |
| July 29 | "Despacito" | Luis Fonsi and Daddy Yankee featuring Justin Bieber |
| August 5 | "Despacito" | Luis Fonsi and Daddy Yankee featuring Justin Bieber |
| August 12 | "Despacito" | Luis Fonsi and Daddy Yankee featuring Justin Bieber |
| August 19 | "Despacito" | Luis Fonsi and Daddy Yankee featuring Justin Bieber |
| August 26 | "There's Nothing Holdin' Me Back" | Shawn Mendes |
| September 2 | "There's Nothing Holdin' Me Back" | Shawn Mendes |
| September 9 | "Attention" | Charlie Puth |
| September 16 | "Attention" | Charlie Puth |
| September 23 | "Attention" | Charlie Puth |
| September 30 | "Attention" | Charlie Puth |
| October 7 | "Slow Hands" | Niall Horan |
| October 14 | "Strip That Down" | Liam Payne featuring Quavo |
| October 21 | "Strip That Down" | Liam Payne featuring Quavo |
| October 28 | "Look What You Made Me Do" | Taylor Swift |
| November 4 | "Sorry Not Sorry" | Demi Lovato |
| November 11 | "Feel It Still" | Portugal. The Man |
| November 18 | "Feel It Still" | Portugal. The Man |
| November 25 | "Feel It Still" | Portugal. The Man |
| December 2 | "Thunder" | Imagine Dragons |
| December 9 | "Havana" | Camila Cabello featuring Young Thug |
| December 16 | "Havana" | Camila Cabello featuring Young Thug |
| December 23 | "Havana" | Camila Cabello featuring Young Thug |
| December 30 | "Havana" | Camila Cabello featuring Young Thug |