The second season of the American television medical drama Grey's Anatomy commenced airing on the American Broadcasting Company (ABC) on September 25, 2005, and concluded on May 15, 2006. The season was produced by Touchstone Television in conjuction with Shondaland production company and The Mark Gordon Company, the showrunner being Shonda Rhimes. Actors Ellen Pompeo, Sandra Oh, Katherine Heigl, Justin Chambers, and T. R. Knight reprised their roles as surgical interns Meredith Grey, Cristina Yang, Izzie Stevens, Alex Karev, and George O'Malley respectively. Previous main cast members Chandra Wilson, James Pickens, Jr., Isaiah Washington and Patrick Dempsey also returned, while Kate Walsh, who began the season in a recurring capacity, was promoted to series-regular status, after appearing in 7 episodes as a guest-star. Internationally, the season was distributed by Buena Vista International Television.

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.