Rihanna led all artists in nominations for the upcoming 2011 Billboard Music Awards, followed by rapper Eminem and Lady Gaga.  The finalists were announced at a press conference Wednesday morning, and the R&B star was named as a finalist in a total of 18 categories.  Eminem was named a finalist in 16 categories, while Gaga received nods in 12 categories.  Pop singers Bruno Mars and Justin Bieber rounded out the top five in nominations, as each was named a finalist in 11 categories.

The winners will be announced at a ceremony May 22nd at the MGM Grand in Las Vegas, Nevada.  The ceremony will air on CBS, and tickets for the event are now on sale from Ticketmaster.  For a complete breakdown of finalists in all 46 categories, Click Here.