The singer - who is signed to Justin Bieber's Schoolboy Records - has topped this week's chart with her latest cut 'Call Me Maybe', pushing Gotye's 'Somebody That I Used To Know' down to two.
David Guetta is at three with 'Titanium' and Nicki Minaj falls a spot to four with 'Starships'.
Katy Perry is the highest new entry with 'Part of Me' landing at number six, trailed by Flo Rida's 'Wild Ones' at seven and Jedward's 'Waterlines' at eight.
Labrinth's 'Last Time' enters at number 17, Coldplay's 'Charlie Brown' moves up to 20 and JLS's 'Proud' debuts at number 28.
Further down the chart, Sean Paul's latest single 'She Doesn't Mind' premieres at number 36, while Olly Murs's 'Oh My Goodness' climbs to number 39.
This week's Irish Top 10 is as follows:
1. (5) Carly Rae Jepsen: 'Call Me Maybe'
2. (1) Gotye feat. Kimbra: 'Somebody That I Used To Know'
3. (8) David Guetta feat. Sia: 'Titanium'
4. (3) Nicki Minaj: 'Starships'
5. (2) Emeli Sandé: 'Next To Me'
6. (-) Katy Perry: 'Part of Me'
7. (4) Flo Rida feat. Sia: 'Wild Ones'
8. (47) Jedward: 'Waterlines'
9. (6) David Guetta feat. Nicki Minaj: 'Turn Me On'
10. (10) Bressie: 'Breaking My Fall'
Watch the music video for Carly Rae Jepsen's 'Call Me Maybe' below: