The Hon. Unity Valkyrie Mitford (August 8, 1914 - May 28, 1948), was one of the noted Mitford sisters. She is said to have been conceived in the mining town of Swastika, Ontario and born in London, England, a daughter of the 2nd Baron Redesdale. She was also a cousin of Clementine Hozier , the wife of Winston Churchill.

Educated at home, she eventually became a devout believer of fascism. In 1933, Mitford traveled to Nuremberg, Germany for a rally and met the man she had become obsessed with, Adolf Hitler. She became a member of Adolf Hitler's entourage and a passionate though naïve supporter of National Socialism, along with her sister Diana Mitford, who married the British fascist leader Sir Oswald Mosley.

British SIS reports from 1936 stated that she saw a lot of Hitler whenever he was in Munich and they viewed her as "more Nazi than the Nazis." The same report said that she gave the "Hitler salute" to the British Consul General in Munich who immediately requested that her passport be impounded.

When Britain declared war on Germany in September of 1939, a distraught Mitford sent a farewell letter to Hitler and shot herself in the head in the English Garden in Munich. The suicide attempt failed and she returned to England, mentally damaged. She spent the rest of her life on the island of Inchkenneth . Doctors had decided it was too dangerous to remove the bullet, and she eventually died of meningitis caused by the cerebral swelling around the lodged bullet.

Mitford was interred in the Swinbrook Churchyard, Oxfordshire, England.

There is a legend that it was Unity Mitford who suggested to Hitler that he adopt the swastika as the Nazi symbol due to the place of her conception. This is highly unlikely given that Mitford would have been a child when the Nazi movement developed and as the swastika had been used as a symbol of the far right nationalist movement in Germany since before she was born.