"Serenade to an Old-Fashioned Girl" is a charming song from the operetta "The Vagabond King" by Rudolf Friml, with lyrics by Brian Hooker and William H. Post. The operetta, set in medieval Paris, was a major Broadway success. The song embodies a nostalgic, tender sentiment popular in the early 20th century. Bing Crosby's later recording helped popularize it beyond the stage.