Her family released a statement, saying Summer died Thursday morning and that they "are at peace celebrating her extraordinary life and her continued legacy."
"Words truly can't express how much we appreciate your prayers and love for our family at this sensitive time," the statement read. She had been living in Englewood, Fla., with her husband Bruce Sudano.
Summer came to prominence just as disco was burgeoning, and came to define the era with a string of No. 1 hits and her beauty queen looks.
Disco became as much defined by her sultry, sexual vocals — her bedroom moans and sighs — as the relentless, pulsing rhythms of the music itself.
"Love to Love You Baby," with its erotic moans, was her first hit and one of the most scandalous songs of the polyester-and-platform-heel era.
Unlike some other stars of disco who faded as the music became less popular, Summer was able to grow beyond it and later segued to a pop-rock sound. She had one of her biggest hits in the 1980s with "She Works Hard For The Money," which became another anthem, this time for women's rights.
Soon after, Summer became a born-again Christian and faced controversy when she was accused of making anti-gay comments in relation to the AIDS epidemic. Summer denied making the comments, but was the target of a boycott.
Still, even as disco went out of fashion she remained a fixture in dance clubs, endlessly sampled and remixed into contemporary dance hits.
Summer, real name LaDonna Adrian Gaines, was born in 1948 in Boston. She was raised on gospel music and became the soloist in her church choir by age 10.
"Love to Love You Baby" was her U.S. chart debut and the first of 19 No. 1 dance hits between 1975 and 2008 — second only to Madonna.
During the disco era she burned up the charts: She was the only artist to have three consecutive double-LPs hit No. 1, "Live and More," ''Bad Girls" and "On the Radio." She was also the first female artist with four No. 1 singles in a 13-month period, according to the Rock Hall of Fame, where she was a nominee this year.
She was never comfortable with the "Disco Queen" label. Musically, she began to change in 1979 with "Hot Stuff," which had a tough, rock 'n' roll beat. Her diverse sound helped her earn Grammy Awards in the dance, rock, R&B and inspirational categories.
Dionne Warwick said in a statement that she was sad to lose a great performer and "dear friend."
"My heart goes out to her husband and her children," Warwick said. "Prayers will be said to keep them strong."
Summer released her last album, "Crayons," in 2008. It was her first full studio album in 17 years. She also performed on "American Idol" that year with its top female contestants.