Eilish, a seven-time GRAMMY winner, won the award alongside her brother and creative partner Finneas.
Eilish was up against Beyonce, Jay Z and Kid Cudi, Ariana Grande and Lin-Manuel Miranda in the category at the Critics Choice Awards.
With the win, Eilish inches closer to her first-ever Oscar.
Following news of their Academy Award nomination in February, Eilish and Finneas released a statement to ET, saying, "Words cannot describe how honored and excited we are to have been nominated for an Academy Award for our song 'No Time To Die.' It was a lifelong dream of ours to write a Bond theme, and one we never thought would ever come true. It’s completely unbelievable that we are here being recognized for this song, and this is a peak life experience for us as songwriters and artists. To be recognized today among these other incredible nominees is something we most certainly do not take for granted."