Miranda Otto (born 16 December 1967) is an Australian actress. The daughter of actors Barry and Lindsay Otto and the sister of Gracie Otto, she began acting at age nineteen, and has performed in a variety of low-budget and major studio films.

Her first major film appearance was in the 1986 film 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, she gained Hollywood’s attention after appearing in supporting roles in The Thin Red Line (1998) and What Lies Beneath (2000). Her breakthrough role was in 2002, when her character Éowyn appeared in The Lord of the Rings trilogy.

Her private life, including her relationships with actors Richard Roxburgh and Peter O’Brien, has been much discussed in the media. In 2008, she starred in the now-cancelled American television series Cashmere Mafia and will appear in the film In Her Skin.