Sienna Rose Miller (born December 28, 1981) is an English model and actress.

Born in New York City, she moved to England as a child and attended the Heathfield School in Ascot, Berkshire. She later attended the Lee Strasberg Institute in New York City.

Her father is Edward Miller, an American banker; her mother is Jo Miller, an American actress who ran Lee Strasberg's acting academy in London. For much of her childhood and adolescence, her stepmother was the English interior decorator Kelly Hoppen.

Miller has acquired only a few minor roles; the most prominent of these was in the television series Keen Eddie. She also appeared in the 2004 remake of the 1966 movie Alfie. In 2005 she made her West End debut as Celia in Shakespeare's As You Like It to lukewarm praise. (The Guardian commented "if she were in a girls' school show, rather than the West End, you would think her well above average.") However, when Helen McCrory, the British actress playing Rosalind, fell ill, Miller took over her role for that evening's performance.

On Christmas Day of 2004 she became engaged to Jude Law (whom she co-starred with in Alfie). On July 18, 2005, Law issued a public apology to her for having an affair with Daisy Wright, the nanny of his children, after the story appeared in British tabloids. Pictures have shown Miller not wearing her engagement ring, and strong doubt existed as to whether they would still marry.

On October 9, 2005 News of the World revealed that Miller had been conducting an affair with Daniel Craig whilst at the same time expressing her feelings of betrayal and upset at Law's affair. Law is reported to have thrown her out of their North London home in disgust at the news.

On October 12, 2005 Miller and Law ended their engagement