220px-Shirelles_tonight's_the_night#10 – The Shirelles – “Will You Love Me Tomorrow” – (1961)

This was the first girl group #1 hit. Written by Carole King and her husband Gerry Goffin, this is the earliest “modern” (i.e. not the Andrews Sisters) girl group song I can think of. It set the stage for everything that came after it, from the Ronettes, to the Supremes, to Destiny’s Child.