Academy Award for Best Actress
Awarded for	"Performance by an actress in a leading role"
Presented by	Academy of Motion Picture Arts and Sciences
Country	United States
First awarded	1929 (for performances in films released in 1927/1928)
First winner	Janet Gaynor, Seventh Heaven, Street Angel, and Sunrise (1927/1928)
Currently held by	Kate Winslet, The Reader (2008)
Official website

Performance by an Actress in a Leading Role is one of the Academy Awards of Merit presented annually by the Academy of Motion Picture Arts and Sciences (AMPAS) to recognize an actress who has delivered an outstanding performance while working within the film industry. Prior to the 49th Academy Awards ceremony (1977), this award was simply known as the Academy Award of Merit for Performance by an Actress. Since its inception, however, the award has commonly been referred to as the Oscar for Best Actress. While actresses are nominated for this award by Academy members who are actors and actresses themselves, winners are selected by the Academy membership as a whole.