Sinéad Marie Bernadette O'Connor ( /ʃɪˈneɪd oʊˈkɒnər/; born 8 December 1966) is an Irish singer-songwriter who rose to fame in the late 1980s with her debut album The Lion and the Cobra. O'Connor achieved worldwide success in 1990 with a cover of the song "Nothing Compares 2 U".

Since then, while maintaining her singing career, she has occasionally encountered controversy, partly due to her statements and gestures such as her ordination as a priest despite being female with a Roman Catholic background, and her expressed strong views on organized religion, women's rights, war, and child abuse.

In addition to her nine solo albums her work includes many singles, songs for films, collaborations with many other artists, and appearances at charity fundraising concerts.

Sinéad O'Connor was born in Glenageary in County Dublin and was named after Sinéad de Valera, wife of Irish President Éamon de Valera and mother of the doctor presiding over the delivery, and Saint Bernadette of Lourdes. She is the third of five children, sister to Joseph, Eimear, John, and Eoin. Joseph O'Connor is a novelist.