Roy Halston Frowick (April 23, 1932 – March 26, 1990), known mononymously as Halston, was an American fashion designer, who rose to international fame in the 1970s.

Halston's minimalist, clean designs, which were often made of cashmere or ultrasuede, were a new phenomenon in the mid-1970s discotheques, and they redefined American fashion. Halston was known for creating a relaxed urban lifestyle for American women. He was frequently photographed at Studio 54 with his close friends Liza Minnelli, Bianca Jagger, Joe Eula, and Andy Warhol.

In the early 1950s, while attending the School of the Art Institute of Chicago, Halston began a business designing and making women's hats. He garnered a well-known clientele and opened a store on Chicago's Magnificent Mile in 1957. He later became the head milliner for high-end New York City department store Bergdorf Goodman. His fame rose when he designed the pillbox hat Jacqueline Kennedy wore to the inauguration of her husband, President John F. Kennedy, in 1961. In the late 1960s, Halston made the transition to women's clothing, opening a boutique on Madison Avenue in New York and started a ready-to-wear line. After several ill-advised business decisions, Halston eventually lost control of his fashion house in the 1980s. He died of AIDS-related cancer in 1990 at the age of 57.

Roy Halston Frowick was born on April 23, 1932, in Des Moines, Iowa, the second son of accountant James Edward Frowick who was of Norwegian descent, and his stay-at-home wife Hallie Mae (née Holmes). Halston developed an early interest in sewing from his grandmother and he began creating hats and altering clothes for his mother and sister. He grew up in Des Moines, and moved to Evansville, Indiana, at the age of 14. He graduated from Benjamin Bosse High School in 1950. He briefly attended Indiana University.

In 1952, Halston moved to Chicago, where he enrolled in a night course at the School of the Art Institute of Chicago, and worked as a window dresser. In 1953, he opened his own hat business. His first customer was radio actress and comedian Fran Allison. Halston's hats were also bought by Kim Novak, Gloria Swanson, Deborah Kerr, and Hedda Hopper.

Halston's first big break came when the Chicago Daily News ran a brief story on his hats. In 1957, he opened his first shop, the Boulevard Salon, on North Michigan Avenue. It was at this point that he began to use his middle name to trade under. During his childhood, he had been referred to as Halston to distinguish between himself and his uncle Roy. Halston moved to New York City in late 1957, first working for milliner Lilly Daché. Within a year, he had been named the co-designer at Daché, became acquainted with several fashion editors and publishers, and left Daché's studio to become head milliner for department store Bergdorf Goodman in their customer milliner salon.

Halston achieved great fame after designing the pillbox hat worn by Jacqueline Kennedy to her husband's presidential inauguration in 1961, and when he moved to designing women's wear, Newsweek dubbed him "the premier fashion designer of all America". When hats fell out of fashion, Halston moved on to designing clothing, made possible by Estelle Marsh, a millionaire from Amarillo, Texas. Marsh was his sole financial backer during this critical time of development. He opened his first boutique on Madison Avenue in 1968. The collection that year included a dark jade velvet wedding gown for advertising executive Mary Wells Lawrence. Lawrence was married to the CEO of Braniff International Airways, Harding Lawrence. She would be instrumental in bringing Halston to Braniff in 1976 to design Braniff's hostess, pilot, ticket agent, and ground personnel uniforms.

Halston launched his first ready-to-wear line, Halston Limited, in 1969. Halston's design was usually simple, minimalist yet sophisticated, glamorous and comfortable at the same time. Halston liked to use soft, luxurious fabric like silk and chiffon. He later told Vogue that he got rid of "...all of the extra details that didn't work—bows that didn't tie, buttons that didn't button, zippers that didn't zip, wrap dresses that didn't wrap. I've always hated things that don't work." Halston changed the fitted silhouette and showed the female body shape by allowing the natural flow of the fabric to create its own shape. Halston said "Pants give women the freedom to move around they've never had before. They don't have to worry about getting into low furniture or low sportscars. Pants will be with us for many years to come—probably forever if you can make that statement in fashion."