Bill Sienkiewicz, born May 3, 1958 in Blakely, Pennsylvania, USA, is a comic book artist best know for Moon Knight. He also worked on Action Comics, JLA, Incredible Hulk, The Titians, Erik Larsen's Aquaman, Trinity, The Question, Superman, Birds of Prey, Superboy, Rom, Savage Sword of Conan, Green Arrow/Black Cannery, The Transformers, Spectacular Spider-Man, Convergence Detective Comics, Dazzler, Kamandi Challenge, Spider-Girl, Hawkman, New Mutants, Deathstroke, The Walking Dead, Detective Comics, Daredevil, Peter David's Spider-Man 2099, Harley Quinn, Defenders, Batman, What If?, Excalibur, Michael Cray, Star Wars, Swamp Thing, Black Widow, The Flintstones, Thor, Raven: Daughter of Darkness, Fantastic Four, Survivor's Club, Wolverine, Savage Dragon and Cerebus.
He was one of the recurring artists on IDW's TMNT Universe.