The 'American Boy' star has been nominated in the Best UK Female, Best R&B/Soul, Best Song, Best Video and Best Album categories.
Leona Lewis will compete against Estelle for three of those trophies, having picked up nominations for Best Video, Best Album and Best UK Female.
Duffy and Adele will also contest the highly competitive Best UK Female award, while rapper Dizzee Rascal, who topped the UK singles charts in July with 'Dance Wiv Me', has picked up a trio of nominations.
Meanwhile, nominees for the prestigious Best International Act gong include Kanye West, Rihanna, Mariah Carey, Jay-Z and Alicia Keys.
This year's MOBO Awards - to be hosted by Run D.M.C. rapper Rev Run and Spice Girl Mel B - take place at London's Wembley Arena on October 15.