George O'Malley, M.D. is a fictional character from the medical drama television series Grey's Anatomy, which airs on ABC in the United States. The character was created by series producer Shonda Rhimes, and was portrayed by actor T. R. Knight from 2005 to 2009. Introduced as a surgical intern at the fictional Seattle Grace Hospital, O'Malley worked his way up to resident level, while his relationships with his colleagues Meredith Grey, Cristina Yang, Izzie Stevens, and Alex Karev formed a focal point of the series. O'Malley married Callie Torres from whom he later separated to pursue a relationship with Stevens. O'Malley also had entertained romantic interests with Grey and Olivia Harper.

Grey's Anatomy is an American medical drama television series focusing on the personal and professional lives of surgical interns, residents, and attendings at the fictional Seattle Grace Hospital, later named the Grey Sloan Memorial Hospital. The series premiered on March 27, 2005, on ABC as a mid-season replacement. The show's title is an allusion to Gray's Anatomy, a classic human anatomy textbook. Writer Shonda Rhimes developed the pilot and served as showrunner, head writer, and executive producer until stepping down in 2015. Set in Seattle, Washington, the series is filmed primarily in Los Angeles, California, and Vancouver, British Columbia.