It's not just the money that got Gaga the top spot. She did make $90 million with her Monster tour, but she ranks No. 1 also because of her 32 million Facebook fans and 9.5 million Twitter followers.
On top of that, her recent single "Born This Way" had a million digital downloads in just five days.
Winfrey did not fall far down the Forbes list, though. She is now No. 2, earning $290 million in 2010. Justin Bieber, U2 and Elton John trailed behind Winfrey on the list.
The list also boasted 19 athletes, including Miami Heat star LeBron James at No. 10 and the Los Angeles Lakers' Kobe Bryant at No. 14.