The 18-year-old pop sensation - the youngest artist ever to record a 007 title track - revealed a haunting ballad exploring themes of lies and betrayal.
It features heavy use of the piano as well as Eilish's signature whisper.
Fans of the franchise will recognise the chord that ends the song, taken from Monty Norman's original Bond theme.
In recording the track, Eilish joins an illustrious list of artists including Adele, Sam Smith, Madonna, Sir Paul McCartney and Dame Shirley Bassey.
"Was I stupid to love you? Was I reckless to help?" Eilish asks on No Time To Die, which she co-wrote with her brother and collaborator Finneas.
It gradually builds up to a point where Eilish sings: "Fool me once, fool me twice. You'll never see me cry, there's just no time to die."
Eilish will perform the song live for the first time at the Brit Awards next week.
No Time To Die has proved to be a hit with both fans and critics.
Bond music historian Jon Burlingame said he would be surprised if the song did not earn Eilish an Oscar nomination next year.
If she did end up winning for best original song, Los Angeles-born Eilish would be following in the footsteps of Adele and Smith, who both won Academy Awards for their Bond tracks.
The teenager revealed she and Finneas wrote it in three days.
"It was honestly like a great process," she told Apple Music's Zane Lowe.
"We got a piece of the script, like the first scene and then wrote the song immediately and we wrote it in three days and we wrote it in Texas and we recorded it in a bunk on the bus, in the basement in the dark."
Following the song's release, Eilish said she is "still in shock" about being asked to record a Bond title track.
Eilish is one of the hottest properties in music and last month became the youngest artist ever to win the big four categories at the Grammys.
For her debut studio album When We All Fall Asleep, Where Do We Go? Eilish took home best new artist, album of the year, record of the year and best pop vocal album.
Her single Bad Guy won song of the year.
No Time To Die is Daniel Craig's fifth and final outing as James Bond. It is due to be released in UK cinemas on April 2.
The official James Bond Twitter account also confirmed Eilish and Finneas will perform No Time To Die at the Brit Awards on February 18, accompanied by composer Hans Zimmer and revered guitarist Johnny Marr.