Marjabelle Young Stewart (1924 – 2007) was an American writer and expert on etiquette.
Born in Council Bluffs, Iowa, she and her sisters lived in an orphanage after her parents' divorce, where her youngest sister died of an illness. After her mother remarried, they returned to live with her. After graduating high school at the age of 17, she married scientist Jack Davison Young and moved to Washington, D.C., where she worked in a naval yard.
Young then became a model and created her own agency in partnership with two other women. She collaborated with Ann Buchwald on two more books and then started writing her own.
She went on to teach etiquette and manners to many children, including the children and grandchildren of several presidents. Her husband started a business to teach etiquette training and she began teaching classes.
She moved to Kewanee, Illinois in 1965 after her divorce and remarriage, and 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), usually in cooperation with department stores.
She died of pneumonia in Kewanee, Illinois at the age of 82.