Actors/Actresses:
* Issa Rae: Actress, writer, producer, and director (Insecure)
* Ian McKellen: Actor (The Lord of the Rings, X-Men)
* Idris Elba: Actor (Luther, Pacific Rim)
* Isla Fisher: Actress (Wedding Crashers, Confessions of a Shopaholic)
* Ingrid Bergman: Actress (Casablanca, Anastasia)
* Isabella Rossellini: Actress (Death Becomes Her, Big Night)
* Imogen Poots: Actress (28 Weeks Later, Green Room)
Musicians:
* Iggy Pop: Singer, songwriter, and musician (The Stooges)
* Iggy Azalea: Rapper and songwriter
* Imagine Dragons: Rock band
* Iron Maiden: Heavy metal band
Athletes:
* Isiah Thomas: Former NBA player and coach
* Ian Wright: Former English footballer
* Ian Poulter: Professional golfer
Other:
* Isaac Newton: Physicist, mathematician, astronomer, and author
* Igor Stravinsky: Composer
* Isadora Duncan: Dancer and choreographer
* Inigo Montoya: Fictional character from The Princess Bride
Note: This list is not exhaustive and there are many other famous people whose last names start with "I."