Edna St. Vincent Millay (February 22, 1892 – October 19, 1950) was an American lyrical poet and playwright. Millay was a renowned social figure and noted feminist in New York City during the Roaring Twenties and beyond. She also wrote prose under the pseudonym Nancy Boyd.

Millay won the 1923 Pulitzer Prize for Poetry for her poem "Ballad of the Harp-Weaver"; she was the first woman and second person to win the award. In 1943, Millay was the sixth person and the second woman to be awarded the Frost Medal for her lifetime contribution to American poetry.

Millay was highly regarded during much of her lifetime, with the prominent literary critic Edmund Wilson calling her "one of the only poets writing in English in our time who have attained to anything like the stature of great literary figures.'' By the 1930s, her critical reputation began to decline, as modernist critics dismissed her work for its use of traditional poetic forms and subject matter, in contrast to modernism's exhortation to "make it new." However, the rise of feminist literary criticism in the 1960s and 1970s revived an interest in Millay's works.

Millay was born Edna Vincent Millay in Rockland, Maine, on February 22, 1892. Her parents were Cora Lounella Buzelle, a custom hair stylist and training nurse for private families, and Henry Tolman Millay, a life insurance agent and teacher who would later become a superintendent of schools. Her middle name derives from St. Vincent's Hospital in New York City, where her uncle's life had been saved from an accident at sea just before her birth. Encouraged to read the classics at home, she was too rebellious to make a success of formal education, but she won poetry prizes from an early age.

Edna's mother attended a Congregational church. In 1904, Cora officially divorced Millay's father for financial irresponsibility and domestic abuse. They had already been separated for some years. Henry and Edna kept a letter correspondence for many years, but he never re-entered the family. Cora and her three daughters – Edna (who called herself "Vincent"), Norma Lounella, and Kathleen Kalloch (born 1896) – moved from town to town, living in poverty and surviving various illnesses. Cora travelled with a trunk full of classic literature, including Shakespeare and Milton, which she read to her children. The family settled in a small house on the property of Cora's aunt in Camden, Maine, where Millay would write the first of the poems that would bring her literary fame. The family's house in Camden was "between the mountains and the sea where baskets of apples and drying herbs on the porch mingled their scents with those of the neighboring pine woods."

The three sisters were independent and outspoken, which did not always sit well with the authority figures in their lives. Millay's grade school principal, offended by her frank attitude, refused to call her Vincent. Instead, he called her by any woman's name that started with a V. At Camden High School, Millay began developing her literary talents, starting at the school's literary magazine, The Megunticook. At 14, she won the St. Nicholas Gold Badge for poetry, and by 15, she had published her poetry in the popular children's magazine St. Nicholas, the Camden Herald, and the high-profile anthology Current Literature.

Millay's fame began in 1912 when, at the age of 20, she entered her poem "Renascence" in a poetry contest in The Lyric Year. The backer of the contest, Ferdinand P. Earle, chose Millay as the winner after sorting through thousands of entries, reading only two lines apiece. Earle sent a letter informing Millay of her win before consulting with the other judges, who had previously and separately agreed on a criterion for a winner to winnow down the massive flood of entrants. According to the remaining judges, the winning poem had to exhibit social relevance, and "Renascence" did not. The entry of Orrick Glenday Johns, "Second Avenue", was about the "squalid scenes" Johns saw on Eldridge Street and lower Second Avenue on New York's Lower East Side. Millay ultimately placed fourth. The press drew attention to the fact that the Millays were a family of working-class women living in poverty. Because the three winners were men, some people felt that sexism and classism were a factor in Millay's poem coming in fourth place.

Controversy in newspaper columns and editorial pages launched the careers of Millay and Johns. Johns, who was receiving hate mail, conceded that he thought her poem was better. "The award was as much an embarrassment to me as a triumph," he said. Johns did not attend the awards banquet. The second-prize winner offered Millay his $250 prize money. In the immediate aftermath of the Lyric Year controversy, wealthy arts patron Caroline B. Dow heard Millay reciting her poetry and playing the piano at the Whitehall Inn in Camden, Maine and was so impressed that she offered to pay for Millay's education at Vassar College.