Gregory Rucka (born November 29, 1969) is an American writer known for the series of novels starring his character Atticus Kodiak, the creator-owned comic book series Whiteout, Queen & Country, Stumptown and Lazarus, as well as lengthy runs on such titles as Detective Comics, Wonder Woman and Gotham Central for DC Comics, and Elektra, Wolverine and The Punisher for Marvel. He has written a substantial amount of supplemental material for a number of DC Comics' line-wide and inter-title crossovers, including "No Man's Land", "Infinite Crisis" and "New Krypton".

Rucka made his debut as a screenwriter with the screenplay for the 2020 film The Old Guard, based on his comic book series of the same name.

Greg Rucka was born to Corrina J. (née Schnitzer) and Noel Michael Rucka, in San Francisco, and raised on the Monterey Peninsula of California, in an area known to the locals as "Steinbeck Country". Rucka is Jewish. He first discovered comics at the Nob Hill Foods supermarket in Salinas, California, where at age five, he first saw digest-sized black and white reprints of Stan Lee and Jack Kirby's work on The Incredible Hulk, which he convinced his mother to buy. He began writing at a young age, and at age 10, he won a county-wide short story contest. He graduated from Vassar College with an A.B. in English. He then enrolled in the University of Southern California's Master of Professional Writing program, graduating with a Master of Fine Arts. He names Douglas Adams as his biggest influence.

Before becoming a professional fiction writer he worked in a number of other occupations, including house painting, restaurant work, emergency medical technician, security guard, technical writer, and fight choreographer.

Rucka's writing career began with the Atticus Kodiak series. Kodiak is a bodyguard whose jobs are rarely as uncomplicated as they at first appear. The series to date consists of Keeper, Finder, Smoker, Shooting at Midnight, Critical Space, Patriot Acts, and Walking Dead. These works garnered Rucka much critical acclaim and comparisons to the elite writers of crime/suspense fiction. The "Atticus" novels are notable for their realism and attention to detail, which is partly a product of Rucka's fight training and experience as an EMT. He has written six non-Atticus books: Fistful of Rain, Alpha, Bravo, A Gentleman's Game, Private Wars, and The Last Run; the latter three are tie-ins to his comic book series Queen & Country.

In 1998, Rucka entered the comics industry with Whiteout, published through Oni Press. Whiteout focuses on a murder in an Antarctic base. It was followed by a sequel, Whiteout: Melt.

The majority of Rucka's work throughout the 2000s was for DC Comics, where he was involved with their main trinity of characters: Superman, Batman and Wonder Woman. Rucka wrote Batman on a regular basis in the Detective Comics series following the events of "No Man's Land'". He wrote the novelization of the year-long arc. While writing Detective Comics, he created a number of background characters that led to the co-creation of Gotham Central with co-writer Ed Brubaker. His Batman work includes such story arcs as "Bruce Wayne: Murderer?" and "Bruce Wayne: Fugitive". as well as the Batman: Death and the Maidens limited series. From October 2003 to April 2006 he wrote Wonder Woman after having previously written the character in the Wonder Woman: The Hiketeia original graphic novel.

From 2002 to 2004, he did some work for Marvel, including the start of the third volume of Wolverine, Elektra and the mini-series Ultimate Daredevil and Elektra. He has worked for Image Comics. The first volume of his series Queen & Country concluded in July 2007 with issue #32.