Marjabelle Young Stewart (16 May 1924 – 3 March 2007) was an American writer and expert on etiquette.
Marjabelle Young Stewart was born in Council Bluffs, Iowa, to Marie and Clarence Cullen Bryant (a great-grandson of poet William Cullen Bryant). She and her three sisters lived in an orphanage after her parents divorced, where her youngest sister died of a mastoid infection at age 2. After her mother remarried they returned to live with her. She attended Thomas Jefferson High School in Council Bluffs. After graduating, she married scientist Jack Davison Young and moved to Washington, D.C. in 1941. She became a model and came into contact with Washington society as a result. She went on to teach etiquette and manners to children, including Richard M. Nixon's daughters, and Dwight D. Eisenhower's granddaughter. She moved to Kewanee, Illinois in 1965 after her divorce from Mr. Young and remarriage to attorney William E. Stewart. She created a network of etiquette classes, which at its height had locations in several hundred U.S. cities. These classes were called White Gloves (for girls) and Blue Blazers (for boys); they usually ran in cooperation with department stores. She wrote fifteen books on etiquette including, Marjabelle Stewart's Book of Modern Table Manners (1981), Can My Bridesmaids Wear Black? And 325 Other Most Asked Questions (1989), and Executive Etiquette in the New Workplace (1996).