Emily "Eve" Best (born 31 July 1971) is an English stage and screen actress and director, known for her television roles as Dr. Eleanor O'Hara in the Showtime series Nurse Jackie (2009–13), First Lady Dolley Madison in the American Experience television special (2011), and Monica Chatwin in the BBC miniseries The Honourable Woman (2014). She also played Wallis Simpson in the 2010 film The King's Speech.

Best won the 2005 Olivier Award for Best Actress for playing the title role in Hedda Gabler. She made her Broadway debut in the 2007 revival of A Moon for the Misbegotten, winning the Drama Desk Award for Outstanding Actress in a Play, and receiving the first of two nominations for the Tony Award for Best Actress in a Play; the second was for the revival of The Homecoming in 2008. She returned to Broadway in the 2015 revival of Old Times.