Penn Fraser Jillette (born March 5, 1955) is an American magician, actor, comedian, musician, inventor, television presenter, and author, best known for his work with fellow magician Teller as half of the team Penn & Teller. The duo has been featured in numerous stage and television shows, such as Penn & Teller: Fool Us and Penn & Teller: Bullshit!, and is as of 2025 headlining in Las Vegas at The Rio. Jillette serves as the act's orator and raconteur.

Jillette has published eight books, including the New York Times Bestseller, God, No!: Signs You May Already Be an Atheist and Other Magical Tales. He is also known for his advocacy of atheism, scientific skepticism, the First Amendment, as well as previously identifying as a libertarian, a position he disavowed in 2020.

Jillette was born in Greenfield, Massachusetts. His mother, Valda Rudolph Jillette (née Parks; 1909–2000), was a secretary, and his father, Samuel Herbert Jillette (1912–1999), worked at Greenfield's Franklin County Jail. Jillette became an atheist in his early teens after reading the Bible. He was subsequently asked to leave the church, after asking questions in a youth group that purportedly also made skeptics of his peers. Jillette became disenchanted with traditional illusionist acts that presented the craft as authentic magic, such as The Amazing Kreskin on The Tonight Show Starring Johnny Carson.

At age eighteen, he saw a show by illusionist James Randi, and became enamored of his approach to magic that openly acknowledged deception as entertainment rather than a mysterious supernatural power. Jillette regularly acknowledges Randi as the one person on the planet he loved the most besides members of his family.

Jillette worked with high school classmate Michael Moschen in developing and performing a juggling act during the years immediately following their 1973 graduation. In 1973, Jillette graduated from Ringling Bros. and Barnum & Bailey Clown College. In 1974, he was introduced to Teller by Weir Chrisemer, a mutual friend. The three then formed a three-person act called Asparagus Valley Cultural Society which played their first act together on August 19, 1975, at the Minnesota Renaissance Festival, and later in San Francisco. In 1981, he and Teller teamed up as Penn & Teller, and went on to do a successful Off Broadway and later Broadway theatre show called "Penn & Teller" that toured nationally.

Jillette served as host and presenter of the first touring performance by avant-garde band the Residents in 1983. The performance (titled The Mole Show and based on their "Mole trilogy" of albums) featured Jillette coming out between songs telling long and intentionally pointless stories. The show was designed to appear to fall apart as it progressed; Jillette pretended to grow angrier with the crowd, and lighting effects and music would become increasingly chaotic, all building up to the point where he was dragged off stage and returned, handcuffed to a wheelchair, to deliver his last monologue. During one performance, an audience member assaulted Jillette while he was handcuffed to the wheelchair. In later years, Jillette would contribute to two documentary films about the Residents.

Jillette was a contributor to the now-defunct PC/Computing magazine, having a regular back-section column between 1990 and 1994.

Jillette was the primary voice announcer for the U.S.-based cable network Comedy Central in the 1990s through the early 2000s.