Katherine Chancellor is a fictional character from the CBS Daytime soap opera The Young and the Restless, portrayed by Jeanne Cooper. Created and introduced by show creator William J. Bell in November 1973, Cooper's Katherine was introduced in an effort to increase the show's struggling ratings. When Bell's plan proved successful, Cooper was signed to a contract. Cooper went on to become one of the longest-running cast members in the show's history, ending her nearly 40-year run on May 3, 2013, five days before her death.

Wilma Jeanne Cooper was an American actress, best known for her role as Katherine Chancellor on the CBS soap opera The Young and the Restless (1973–2013). At the time of her death, she had played Katherine for over 40 years, and her name appears on the list of longest-serving soap opera actors in the United States.