List of number-one singles of 2018 (Australia)
The ARIA Singles Chart ranks the best-performing singles in Australia. Its data, published by the Australian Recording Industry Association, is based collectively on the weekly physical and digital sales and streams of singles. In 2018, 13 singles have claimed the top spot, including Ed Sheeran's "Perfect", which started its peak position in 2017. Six acts, Ariana Grande, Ty Dolla Sign, Childish Gambino, Dean Lewis, George Ezra and Bradley Cooper, reached the top spot for the first time.
earned their second number-one single in 2018 with "Youngblood" which spent eight weeks at number one. They became the first Australians along with Dean Lewis and his song "Be Alright" to reach number one in Australia since 2016.
earned her first and second number-one singles in 2018 with "No Tears Left to Cry" and "Thank U, Next", the former of which spent one week at number one and the latter which spent six weeks at number one.
earned her third number-one single with the 1994 single, "All I Want for Christmas Is You" in 2018. It was the first Christmas song to reach number one in Australia in nearly thirty-four years; the last being "Do They Know It's Christmas?" by Band Aid in January 1985. It was also the oldest song to initially reach number one in the country, taking twenty-four years to reach the top spot. Carey's last number one in Australia was "We Belong Together", which reached number one in 2005.
Chart history
| Issue date | Song | Artist | |
| 1 January | "Perfect" | Ed Sheeran | |
| 8 January | "Perfect" | Ed Sheeran | |
| 15 January | "Perfect" | Ed Sheeran | |
| 22 January | "Perfect" | Ed Sheeran | |
| 29 January | "Perfect" | Ed Sheeran | |
| 5 February | "God's Plan" | Drake | |
| 12 February | "God's Plan" | Drake | |
| 19 February | "God's Plan" | Drake | |
| 26 February | "God's Plan" | Drake | |
| 5 March | "God's Plan" | Drake | |
| 12 March | "God's Plan" | Drake | |
| 19 March | "God's Plan" | Drake | |
| 26 March | "God's Plan" | Drake | |
| 2 April | "God's Plan" | Drake | |
| 9 April | "God's Plan" | Drake | |
| 16 April | "God's Plan" | Drake | |
| 23 April | "Nice for What" | Drake | |
| 30 April | "No Tears Left to Cry" | Ariana Grande | |
| 7 May | "Psycho" | Post Malone featuring Ty Dolla Sign | |
| 14 May | "Nice for What" | Drake | |
| 21 May | "This Is America" | Childish Gambino | |
| 28 May | "Youngblood" | 5 Seconds of Summer | |
| 4 June | "Youngblood" | 5 Seconds of Summer | |
| 11 June | "Youngblood" | 5 Seconds of Summer | |
| 18 June | "Youngblood" | 5 Seconds of Summer | |
| 25 June | "Youngblood" | 5 Seconds of Summer | |
| 2 July | "Youngblood" | 5 Seconds of Summer | |
| 9 July | "Youngblood" | 5 Seconds of Summer | |
| 16 July | "Youngblood" | 5 Seconds of Summer | |
| 23 July | "In My Feelings" | Drake | |
| 30 July | "In My Feelings" | Drake | |
| 6 August | "In My Feelings" | Drake | |
| 13 August | "In My Feelings" | Drake | |
| 20 August | "Be Alright" | Dean Lewis | |
| 27 August | "Be Alright" | Dean Lewis | |
| 3 September | "Be Alright" | Dean Lewis | |
| 10 September | "Be Alright" | Dean Lewis | |
| 17 September | "Be Alright" | Dean Lewis | |
| 24 September | "Shotgun" | George Ezra | |
| 1 October | "Shotgun" | George Ezra | |
| 8 October | "Shotgun" | George Ezra | |
| 15 October | "Shotgun" | George Ezra | |
| 22 October | "Shotgun" | George Ezra | |
| 29 October | "Shallow" | Lady Gaga and Bradley Cooper | |
| 5 November | "Shallow" | Lady Gaga and Bradley Cooper | |
| 12 November | "Shallow" | Lady Gaga and Bradley Cooper | |
| 19 November | "Thank U, Next" | Ariana Grande | |
| 26 November | "Thank U, Next" | Ariana Grande | |
| 3 December | "Thank U, Next" | Ariana Grande | |
| 10 December | "Thank U, Next" | Ariana Grande | |
| 17 December | "Thank U, Next" | Ariana Grande | |
| 24 December | "Thank U, Next" | Ariana Grande | |
| 31 December | "All I Want for Christmas Is You" | Mariah Carey |