Catherine Anne O'Hara OC (born 1954) is a Canadian-American actress. She is known for her comedy work on Second City Television (1976–84) and Schitt's Creek (2015–2020) and in films such as After Hours (1985), Beetlejuice (1988), Home Alone (1990), Home Alone 2: Lost in New York (1992), and The Nightmare Before Christmas (1993). Her other film appearances include the mockumentary films written and directed by Christopher Guest; Waiting for Guffman (1996), Best in Show (2000), A Mighty Wind (2003), and For Your Consideration (2006).

O'Hara won the 1982 Primetime Emmy Award for Outstanding Writing for a Variety Series for SCTV Network, the Genie Award for Best Supporting Actress for the 1999 film The Life Before This, and was nominated for an Emmy Award for the 2010 television film Temple Grandin. From 2015 to 2020, she starred as Moira Rose on the CBC sitcom Schitt's Creek, for which she won a Primetime Emmy Award, Golden Globe Award, Screen Actors Guild Award, TCA Award and six consecutive Canadian Screen Awards.