The singer will present the main show from Belfast's Odyssey Arena on November 6 and will be the first host in MTV history to lead all multi-platform coverage.
The actress will appear on the main show from 9pm, but will also be offering Twitter updates and behind-the-scenes gossip, as well as playing commentator on mtvema.com.
Talking about her appointment, Gomez said: "I'm so excited to be the host of the 2011 MTV EMAs - it's a dream come true!
"This is such a huge event that always recognises the biggest stars in music from across the globe, so it's a real honour to be MC at this year's show."
Viewers can vote for their favourite MTV EMAs nominees via the award show's official website.
This year's list recognises talent from Adele, Katy Perry, Lady GaGa and Bruno Mars, among others.
The MTV EMAs 2011 air Sunday, November 6 on MTV.
> MTV EMA nominations 2011: In full
Watch the music video for Selena Gomez & the Scene's recent single 'Love You Like A Love Song' below: