Sharapova, the highest-ranked 2012 Olympian on the list, came in fourth place and Williams in sixth. They were the only females in the Top 10 and the only tennis players.
Sharapova's 2012 was highlighted by a French Open triumph that made her the sixth woman in the Open Era to capture the career Grand Slam, and a silver medal at the London Olympics, where she fell in the final to Williams.
Sharapova is no stranger to off-court accolades. Among her recent feats are earlier this year leading Forbes' list of highest-paid female athletes for the eighth straight year, and in 2011 ranking eighth on its list of Most Valuable Brand Names in sports and 80th on its list of Most Powerful Celebrities. She also came in first place on the Bing list last year, and Williams came in third.
NFL superstar quarterback Peyton Manning topped this year's Bing list. Here is the complete Top 10:
1. Peyton Manning (NFL)
2. Tiger Woods (PGA)
3. Tim Tebow (NFL)
4. Maria Sharapova (WTA)
5. Kobe Bryant (NBA)
6. Serena Williams (WTA)
7. Lamar Odom (NBA)
8. LeBron James (NBA)
9. Cristiano Ronaldo (BBVA)
10. Terrell Owens (previously of NFL)