Gaga, 24, real name Stefani Germanotta, is the seventh most powerful woman in the world, according to Forbes magazine's annual 100 Most Powerful Women list.
The Alejandro singer beat Queen Elizabeth II, 84, who came in 41st place.
US President Barack Obama's wife Michelle, 46, finished top, closely followed by Kraft Foods boss Irene Rosenfeld, 57, and talk show host Oprah Winfrey, 56.
Angela Merkel, 56, the German Chancellor, and US Secretary of State Hillary Clinton, 62, made up the top five women.