Elizabeth Chase Olsen (born February 16, 1989) is an American actress. She gained worldwide recognition for her portrayal of Wanda Maximoff / Scarlet Witch in the Marvel Cinematic Universe since 2014, with her performance in the miniseries WandaVision (2021) earning her nominations for both a Primetime Emmy Award and a Golden Globe Award.

Born in Sherman Oaks, California, Olsen began acting at age four alongside her sisters Mary-Kate and Ashley Olsen. She had her debut film role in the thriller Martha Marcy May Marlene in 2011, for which she received praise. Olsen received a BAFTA Rising Star Award nomination and graduated from New York University two years later.

Outside of her work with Marvel, Olsen starred in the monster film Godzilla (2014), the mystery film Wind River (2017), and the dramas Ingrid Goes West (2017) and His Three Daughters (2024). She also starred as a widow in the drama series Sorry for Your Loss (2018–2019) and as Candy Montgomery in the miniseries Love & Death (2023), with the latter earning her another nomination for a Golden Globe Award.

Elizabeth Chase Olsen was born on February 16, 1989, in Sherman Oaks, California. Her mother, Jarnie, is a former dancer and personal manager, while her father, Dave, is a real estate agent. Their father has Norwegian ancestry while their mother is of French, German and Italian ancestry. She is the younger sister of twin fashion designers Mary-Kate and Ashley Olsen, who became successful television and film actresses as children. Olsen also has an older brother, James "Trent" Olsen (born 1984). Her parents divorced in 1996, and their father remarried that same year. Through him and his second wife, McKenzie, the four siblings have two half-siblings: Courtney and Jake.

Olsen began acting when she was four years old, appearing in Mary-Kate and Ashley's projects, including the 1994 television film How the West Was Fun and the straight-to-video series The Adventures of Mary-Kate & Ashley. After her sisters' music success with their sophomore album I Am The Cute One, Olsen was signed by their label BMG Kidz in August 1994. Despite being signed to the children's music label, Olsen never recorded any music. As a child, she took ballet lessons and acting classes and spent time at musical theatre camp. For a time, she chose ballet over acting and at one point wanted to work as an accountant at Wall Street.

Olsen got back into acting while in high school, but nearly quit pursuing acting in 2004 due to the media attention toward Mary-Kate's eating disorder. She went to Campbell Hall School in Studio City, California. Olsen attended New York University (NYU)'s Tisch School of the Arts. During college, she took classes at Atlantic Theater Company. She also spent a semester at the Moscow Art Theatre School in Russia, where she began to take acting more seriously than she had before. She attained understudy roles in the 2008 off-Broadway production of the play Dust and the 2009 Broadway production of the play Impressionism, which led to her securing an agent. Olsen graduated from NYU in January 2013.

Olsen made her film debut in the 2011 thriller film Martha Marcy May Marlene. The film, along with her performance, received critical acclaim following its premiere at the Sundance Film Festival. Olsen earned several award nominations for her portrayal of the titular Martha, a young woman suffering from delusions after fleeing her life in a cult and returning to her family, including those for the Critics' Choice Movie Award for Best Actress and the Independent Spirit Award for Best Female Lead. She attributed her interest in the character to her own fascination with mental illnesses. Olsen next appeared in the horror film Silent House, which garnered her "rave reviews". Despite premiering at the Sundance Film Festival alongside Martha Marcy May Marlene, it was released in 2012, during which she also starred in the thriller Red Lights and the comedy Liberal Arts.

In January 2013, Olsen garnered a nomination for the BAFTA Rising Star Award at the 66th British Academy Film Awards. Later that year, she played Edie Parker, novelist Jack Kerouac's first wife and the author of the Beat Generation memoir You'll Be Okay, in the biographical drama Kill Your Darlings. She also appeared in the American remake of the 2003 South Korean film Oldboy, playing Marie Sebastian, a nurse who helps the protagonist, played by Josh Brolin, find his daughter. That same year, she starred as the titular Juliet in an off-Broadway production of the play Romeo and Juliet by William Shakespeare. The New York Times critic Ben Brantley described her portrayal as "alternating between saucy petulance and hysteria".