Carlotta Monterey (born Hazel Nielsen Tharsing; December 28, 1888 – November 18, 1970) was an American stage and film actress.

[2][3] After she won the title of "Miss California" in a beauty contest, she traveled to London to study acting with Sir Herbert Beerbohm Tree.

[2] She adopted the name Carlotta Monterey after her return to the United States at the start of World War I and pursued a career in the theatre.

After divorcing her third husband, the illustrator Ralph Barton, in 1926, she became romantically involved with Eugene O'Neill, whom she had met in 1922 when she acted in a production of his play The Hairy Ape.

A resident of the Valley Nursing Home in Westwood, New Jersey, Monterey died there on November 18, 1970.