Cynthia Ann Stephanie Lauper (/ˈlɔːpər/ LAW-pər; born June 22, 1953) is an American singer, songwriter and actress. Known for her distinctive image, featuring a variety of hair colors and eccentric clothing, and for her powerful four-octave vocal range, Lauper has sold over 50 million records worldwide. She has also been celebrated for her humanitarian work, particularly as an advocate for LGBTQ rights in the United States.

Her debut studio album, She's So Unusual (1983), was the first debut album by a female artist to achieve four top-five hits on the Billboard Hot 100—"Girls Just Want to Have Fun", "Time After Time", "She Bop", and "All Through the Night"—and earned Lauper the Best New Artist award at the 27th Annual Grammy Awards in 1985. The music video for "Girls Just Want to Have Fun" won the Best Female Video Award at the inaugural 1984 MTV Video Music Awards and has been recognized by MTV, VH1 and Rolling Stone as one of the greatest music videos of the era. Her second studio album, True Colors (1986), scored two more top-five hits; the title track and "Change of Heart". Lauper's chart success continued with the singles "The Goonies 'R' Good Enough" (1985), "I Drove All Night" (1989) and into the 2000s with multiple #1 hits on the Hot Dance Club Play charts, "Same Ol' Story, and, "Into the Nightlife" (2008).

Since 1983, Lauper has released twelve studio albums and participated in many other projects. In 2010, Memphis Blues became Billboard's most successful blues album of the year, remaining at number one on the Billboard Blues Albums chart for 13 consecutive weeks. In 2013, she won the Tony Award for Best Original Score for composing the Broadway musical Kinky Boots, making her the first woman to win the category by herself. The musical was awarded five other Tonys, including Best Musical. In 2014, Lauper was awarded the Grammy Award for Best Musical Theater Album for the cast recording. In 2016, the West End production won the Laurence Olivier Award for Best New Musical.

Lauper's accolades include two Grammy Awards, a Primetime Emmy Award, a Tony Award, three MTV Video Music Awards, four Billboard Music Awards, two American Music Awards and a star on the Hollywood Walk of Fame. She is one of the few singers to win three of the four major American entertainment awards (EGOT). In 2015, she was inducted into the Songwriters Hall of Fame. Lauper was selected for induction into the Rock and Roll Hall of Fame in 2025. Her debut studio album ranked among Rolling Stone's list of the 500 Greatest Albums of All Time, while "Time After Time" was included in VH1's list of the 100 Best Songs of the Past 25 years. VH1 has ranked Lauper No. 58 of the 100 Greatest Women of Rock & Roll.

Lauper was born in Brooklyn, New York City, to a Catholic family. Her father, Fred, was of Swiss-German descent, and a descendant of Christen Lauper, a leader of the Swiss peasant war of 1653. Her mother, Catrine (née Gallo; 1930–2022), was of Italian (Sicilian) descent. Lauper's siblings are her younger brother Fred (nicknamed Butch), and older sister Ellen. Lauper's parents divorced when she was five. Her mother remarried and divorced again.

Lauper grew up in the Ozone Park neighborhood of Queens and, as a child, listened to such artists as the Beatles and Judy Garland. At age 12, she began writing songs and playing an acoustic guitar given to her by her sister.

Lauper expressed herself with a variety of hair colors and eccentric clothing, and took a friend's advice to spell her name as "Cyndi" rather than "Cindy". Her unconventional sense of style led to classmates bullying and throwing stones at her.

Lauper went to Richmond Hill High School, but was expelled although she later earned her General Educational Development (GED). She ran away from home at 17 to escape her abusive stepfather, intending to study art. Her journey took her to Canada, where she spent two weeks in the woods with her dog Sparkle, trying to find herself. She eventually traveled to Vermont, where she took art classes at Johnson State College and supported herself working odd jobs. In 2019, Lauper gave the commencement address at Northern Vermont University – Johnson, the academic institution that includes Johnson State. At this event, NVU bestowed upon her an honorary degree of Doctor of Letters.