The 42-year-old singer was followed by Oprah Winfrey in second place and Justin Bieber in third place.
Lopez landed on top of the 'World's Most Powerful Celebrities' list due to earning $52 million over the last 12 months and a "massive amount of fame" from her music, American Idol and her endorsements.
'Marry The Night' popstar Lady GaGa, who was last year's 'Most Powerful Celebrity', came in fifth place.
The top ten 'World's Most Powerful Celebrities' are as follows:
- Jennifer Lopez
- Oprah Winfrey
- Justin Bieber
- Lady GaGa
- Britney Spears
- Kim Kardashian
- Katy Perry
- Tom Cruise
- Steven Spielberg
The list is based on "money and fame", with fame defined as media visibility, not just in traditional forms like print, television and radio, but also online and on social media networks.
A celebrity's earnings were taken from his or her pre-tax income between May 1, 2011, and May 1, 2012, which does not include the deductions of management, agent and attorney fees.
Watch the music video for Jennifer Lopez's 'Dance Again' below: