The Doris Day Animal Foundation confirmed the actress and animal activist died early on Monday at her Carmel Valley home in California.
It is believed Day was surrounded by close friends and family at the time of her passing and "had been in excellent physical health for her age, until recently contracting a serious case of pneumonia," according to reports.
Day starred in a number of blockbusters including Calamity Jane, Love Me or Leave Me, Pillow Talk and Midnight Lace.
"I get so many love letters from fans as young as 8 years old, telling me they were introduced by my films and music by their great-grandmothers, and my movies make them happy," Day told The Hollywood reporter earlier this year.
"Different films resonate with viewers for different reasons, but the common thread seems to be that my films are uplifting.
Asked to describe her legacy in film and the impact she has had on 20th century cinema, Day simply replied: "I enjoyed working and always tried to do the best job I could with every role. I’m thrilled to know that people are still watching my films and are uplifted by them."