Imelda Mary Philomena Bernadette Staunton (born 9 January 1956) is an English actress and singer. After training at the Royal Academy of Dramatic Art, Staunton began her career in repertory theatre in 1976 and appeared in various theatre productions in the United Kingdom.

Throughout her career, Staunton has appeared in a variety of plays and musicals in London, winning four Laurence Olivier Awards: three for Best Actress in a Musical for her roles in the musicals Into the Woods, Sweeney Todd and Gypsy, and one for Best Actress in a Supporting Role in a Play for her work in The Chorus of Disapproval and The Green Bush. Other stage work includes The Beggar's Opera, The Wizard of Oz, Uncle Vanya, Guys and Dolls, Entertaining Mr Sloane and Good People. She has been nominated for 13 Olivier Awards.

In film, Staunton has appeared in Antony and Jane; in several supporting roles in Kenneth Branagh's comedy Peter's Friends, his adaptation of Much Ado About Nothing; Ang Lee's adaptation of Sense and Sensibility; and the costume romantic comedy Shakespeare in Love. Critics praised her performance in the title role in Mike Leigh's Vera Drake, for which she won the BAFTA Award for Best Actress and the Volpi Cup for Best Actress at the Venice Film Festival, and was also nominated for an Academy Award, a Golden Globe and a Screen Actors Guild Award for Best Actress. She later gained wider recognition for her role as Dolores Umbridge in the Harry Potter films Order of the Phoenix and Deathly Hallows – Part 1. She continued to play supporting roles in Mary Poppins, Goodbye, reunited with Leigh in Another Year and in the film continuation of Downton Abbey. She played human rights activist Hefina Headon in the historical film Pride and the lead role in the British comedy Finding Your Feet. She also voiced roles in Chicken Run, Arthur Christmas and Paddington.

On television, Staunton appeared in the sitcoms Up the Garden Path and Is It Legal?. Her role in My Family and Other Animals earned her a nomination for an International Emmy Award for Best Actress, and her roles in Return to Cranford and The Girl earned her nominations for the BAFTA TV Award for Best Supporting Actress. For the latter, she was also nominated for a Primetime Emmy Award for Outstanding Supporting Actress in a Miniseries or a Movie. She played Queen Elizabeth II in the final two seasons of the series The Crown.