The Academy of Motion Picture Arts and Sciences felt the need to not only honor actors for their cinematic performances, but that equal treatment was needed for actresses as well. This practice began in 1928 when Janet Gaynor was rewarded for outstanding performance by a lead actress in 3 different films that year. As was the case with the Best Actor category, the voting process was streamlined so that a nominee would have one eligible film for consideration. Katharine Hepburn holds several records in this category. She has the most all-time wins in the category with 4, the last of which was in 1981 for On Golden Pond. She also holds the all-time mark with 12 Best Actress nominations. She is also one of only two actresses to win this award in consecutive years, doing so in 1967 for Guess Who's Coming to Dinner, and tying for the award in 1968 for her role in The Lion in Winter. Barbra Streisand (for Funny Girl) tied with Hepburn that year. The only other consecutive winner was Luise Rainer for 1936's The Great Ziegfield and 1937's The Good Earth. The most recent winner was Marion Cotillard for her 2007 performance in La Vie en Rose.

1. 1st winner: Janet Haynor in 1928 (for 3 roles)
2. In 1968, both Katharine Hepburn and Barbra Streisand tie in voting and each won an award
3. Luise Rainer and Katharine Hepburn are only actresses to win consecutive Best Actress awards
4. Katharine Hepburn has won the most times with 4
5. Helen Hunt is only actress ever to win Oscar and Emmy awards for Best Actress in same year