Forbes' annual list of the "World's 100 Most Powerful Women" includes 24 CEOs, 15 billionaires and eight heads of state. The women on the list control $1 trillion in annual revenues.
For the fifth consecutive year, German Chancellor Angela Merkel topped the list.
"She oversees the fourth largest economy in the world, but also the largest economy in Europe. The fate of the eurozone rests on her shoulder. With things like the debt crisis in Greece and a connected economy, what she does in Europe affects us all," Forbes Media executive vice president Moira Forbes said.
Presidential candidate Hillary Clinton, who was ranked sixth in 2014, jumped up to number two.
"She is seen as obviously the very likely Democratic candidate, but also possibly the presumptive president of the free world," Forbes said. "When you're seen as having that power in the future, it gives you that power today. She's also banked huge bucks, thanks to her very lucrative speaking engagements. [She] got a lot of controversy around that, but she also still has really favorable poll ratings despite all the issues that she's been having."
Melinda Gates, co-chair of the Bill and Melinda Gates Foundation, was named the third most powerful woman, and Federal Reserve Chair Janet Yellen was the fourth.
General Motors CEO Mary Barra followed at number five.
"[Barra] took the job last year in a very, very challenging time at GM, with the recall crisis," Forbes said.
Barra, who has been CEO since 2014, is the first woman to head a "Big 8" automaker.
"A lot of people questioned whether she could turn around the bureaucratic culture, and in a year, a lot of people have faith that she can turn this company around and deal with the big safety issues they've had," Forbes said.
Forbes also said a third of the women on the list were from Asia, and there were 10 self-made billionaires on the list -- a record number -- including the youngest self-made female billionaire, Theranos CEO Elizabeth Holmes.
See the full list of the most powerful women on Forbes.com.