"Tie a Yellow Ribbon Round the Ole Oak Tree" is a song by Dawn featuring Tony Orlando. It was written by Irwin Levine and L. Russell Brown and produced by Hank Medress and Dave Appell, with Motown / Stax backing vocalist Telma Hopkins, Joyce Vincent Wilson and her sister Pamela Vincent on backing vocals. It was a worldwide hit for the group in 1973.

Who sang tie a yellow ribbon round an old oak tree? OK. Let's think. My stream of consciousness:
To answer this question, we should know that: "Tie a Yellow Ribbon Round the Ole Oak Tree" is a song by Dawn featuring Tony Orlando. The answer is Dawn featuring Tony Orlando.