Christian Ernest Dior (French: [kʁistjɑ̃ djɔʁ]; 21 January 1905 – 24 October 1957) was a French fashion designer and founder of one of the world's top fashion houses, Christian Dior SE. His fashion house is known all around the world, having gained prominence "on five continents in only a decade."

Dior's skills led to his employment and design for various fashion icons in attempts to preserve the fashion industry during World War II. After the war, he founded and established the Dior fashion house, with his collection of the "New Look". In 1947, the collection debuted featuring rounded shoulders, a cinched waist, and very full skirt. The New Look celebrated ultra-femininity and opulence in women's fashion.

Throughout his lifetime, and after his death, he won numerous awards for Best Costume Design.

Dior was born in Granville, a seaside town on the coast of Normandy, France. He was the second of five children born to Maurice Dior, a wealthy fertilizer manufacturer (the family firm was Dior Frères), and his wife, formerly Madeleine Martin. He had four siblings: Raymond (father of Françoise Dior), Jacqueline, Bernard, and Catherine Dior. When Christian was about five years old, the family moved to Paris.

Dior's family had hoped he would become a diplomat, but Dior was interested in art. To make money, he sold his fashion sketches outside his house for about 10 cents each (US$2 in 2025 dollars). In 1928, he left school and received money from his father to finance a small art gallery, where he and a friend sold art by the likes of Pablo Picasso. Alongside managing his art gallery, Dior cultivated friendships with influential artists, including Picasso, Salvador Dalí, Jean Cocteau, and Alberto Giacometti. Immersed in this creative environment, Dior drew inspiration from their work, which shaped his later approach in fashion design. The gallery closed three years later, following the deaths of Dior's mother and brother, as well as financial trouble during the Great Depression that resulted in his father losing control of the family business. Dior had no choice but to find another source of income.

In search of work, Dior again created and sold fashion sketches. Those sketches were discovered by fashion designer Robert Piguet. From 1937, Dior was employed by Piguet, who gave him the opportunity to design for three collections. Dior later said that "Robert Piguet taught me the virtues of simplicity through which true elegance must come." One of his original designs for Piguet, a day dress with a short, full skirt that was in his collection called "Cafe Anglais", was particularly well received. Whilst working for Piguet, Dior worked alongside Pierre Balmain, and was succeeded as house designer by Marc Bohan – who would, in 1960, become head of design for Christian Dior Paris. Dior left Piguet when he was called up for military service.

In 1942, when Dior left the army, he joined the fashion house of Lucien Lelong, where he and Balmain were the primary designers. For the duration of World War II, Dior, as an employee of Lelong, designed dresses for the wives of Nazi officers and French collaborators, as did other fashion houses that remained in business during the war, including Jean Patou, Jeanne Lanvin, and Nina Ricci. His sister, Catherine (1917–2008), a member of the French Resistance, was captured by the Gestapo and sent to the Ravensbrück concentration camp, where she was incarcerated until her liberation in May 1945. In 1947, Dior named his debut fragrance Miss Dior in tribute to her. The story of Dior’s life during WWII and the following few years is featured in the mini-series The New Look.

Dior was known for being superstitious. He often consulted his astrologer before making decisions, and his collections frequently featured talismanic symbols. He also carried a cluster of lucky charms with him, believing they brought him good fortune. At a pivotal moment when industrialist Marcel Boussac offered six million francs to establish Maison Christian Dior, Dior accepted only after receiving approval from two separate clairvoyants.