Jessie, real name Jessica Cornish, won best UK act, best song for Do It Like A Dude and best album for Who You Are and best newcomer at last night's event in Glasgow.
After picking up the best album award, Jessie said: 'I just want to say the biggest thank you to my fans because I watched this last year by myself in my living room and no-one knew who I was.'
But the 23-year-old lost out on the best video award as it went to Tinchy Stryder and Dappy for Spaceship.
Tinie Tempah got the best hip hop prize, Adele was named best R&B/soul act, and Barbadian beauty Rihanna won best international star.
The winners of the prizes, staged at the Scottish Exhibition and Conference Centre and hosted by singer Alesha Dixon and Jason Derulo, were decided by public vote.
The night also included a tribute to Amy Winehouse, led by her goddaughter Dionne Bromfield, who performed Love Is A Losing Game.