The Daily Beast and Newsweek, the hosts of the event, announced Clinton's attendance on Friday.
Actress Meryl Streep, U.S. Ambassador to the United Nations Susan Rice, and Oprah Winfrey will also speak at the summit, set in New York City on April 4 and 5.
Clinton's appearance is likely to reinforce speculation that she is angling to run for president in 2016. Clinton recently announced her support for same-sex marriage, which was also interpreted by some as a sign that she is strongly considering a presidential run. Clinton supported civil unions but opposed same-sex marriage when she ran for president in 2008.
The White House also announced on Friday that Vice President Biden would be the keynote speaker at a pair of high profile fundraiser in Michigan and South Carolina, both coveted primary states. Biden, like Clinton, is rumored to be considering a presidential run in 2016.