Sarah Ellen Polley is a Canadian filmmaker, writer, political activist and retired actress. She first garnered attention as a child actress for her role as Ramona Quimby in the television series Ramona, based on Beverly Cleary's books. This subsequently led to her role as Sara Stanley in the Canadian television series Road to Avonlea (1990–1996). She has starred in many feature films, including The Adventures of Baron Munchausen (1988), Exotica (1994), The Sweet Hereafter (1997), Guinevere (1999), Go (1999), The Weight of Water (2000), No Such Thing (2001), My Life Without Me (2003), Dawn of the Dead (2004), Splice (2009), and Mr. Nobody (2009).

Ramona is a Canadian children's television series which followed the life of eight-year-old title character Ramona Quimby. It was based on the Ramona book series by Beverly Cleary.