According to a list by the charity DoSomething.org, the Bad Romance singer has topped a list of giving stars.
Gaga, real name Stefani Germanotta, earned the title for her work on the 'Don't Ask Don't Tell' campaign and the Hands Up for Marriage Equality event, which supported same-sex marriage.
The 24-year-old was also the face of the MAC Viva Glam range, with all proceeds going to HIV and AIDS charitiies.
Singer Alicia Keys, 29, came in second place, who devoted her time to the fight against HIV and AIDS.
Other celebrities which feature in the top ten include Taylor Swift, Demi Moore and Ashton Kutcher, Nick Jonas, Matt Damon, Ellen DeGeneres, Justin Bieber, Oprah Winfrey and Leonardo DiCaprio.