Miranda Otto (born 16 December 1967) is an Australian actress. The daughter of actors Barry and Lindsay Otto and the sister of actress Gracie Otto, Otto began her acting career in 1986, and has appeared in a variety of independent and major studio films. Otto made her major film debut in Emma's War, in which she played a teenager who moves to Australia's bush country during World War II. After a decade of critically acclaimed roles in Australian films, Otto gained Hollywood's attention during the 1990s after appearing in supporting roles in the films The Thin Red Line and What Lies Beneath. She become a household name in the early 2000s for playing Éowyn in Peter Jackson's The Lord of the Rings film trilogy.

Otto was born in Brisbane to actors Barry and Lindsay Otto. Her half-sister, Gracie, is also an actress.Otto was raised in Newcastle and Brisbane, and briefly resided in Hong Kong following her parents' divorce when she was only six years old. She spent weekends and holidays with her father in Sydney and developed an interest in acting through him.

During her childhood, Otto and her friends wrote scripts and designed costumes and flyers in their spare time. She appeared in several plays at the Nimrod Theatre, which attracted the attention of casting director Faith Martin. Subsequently, Otto received a role in the 1986 World War II drama Emma's War. As a teenager, Otto excelled in academics and in ballet, which she considered as a career option. However, she had to abandon this goal due to moderatescoliosis. Otto graduated from the National Institute of Dramatic Art in Sydney in 1990. Prior to graduation, she appeared in minor film roles including Initiation (1987) and The 13th Floor (1988).

On 1 January 2003, she married actor Peter O'Brien, after the two had met while performing in A Doll's House. Otto and O'Brien have one child, a daughter named Darcey, who was born on 1 April 2005. The pregnancy almost forced her to turn down her role in War of the Worlds. Since the birth of her daughter, Otto has limited her work so she can spend time with her family at their home in Australia.

In a 2004 interview, Otto stated that she hopes she will never be as famous as fellow Australian actress Nicole Kidman because she's "not sure [she] could ever deal with that."