Prince Paul of Yugoslavia, also known as Paul Karađorđević (Serbo-Croatian: Павле Карађорђевић, romanized: Pavle Karađorđević, English transliteration: Paul Karageorgevich; 27 April 1893 – 14 September 1976), was prince regent of the Kingdom of Yugoslavia during the minority of King Peter II. Paul was a first cousin of Peter's father, Alexander I.

Prince Paul of Yugoslavia was the only son of Prince Arsen of Serbia, the younger brother of King Peter I, and of Princess Aurora Pavlovna Demidova. Through his mother, who was the eldest granddaughter on one side of the Swedish-speaking Finnish philanthropist Aurora Karamzin and her Russian husband, Prince Pavel Nikolaievich Demidov, and on the other side of the Russian Prince Peter Troubetzkoy and his wife, Elisabeth Esperovna, born Princess Belosselsky-Belozersky.

At the time of Paul’s birth, the House of Karađorđević was in exile, as the Serbian throne was held by their rivals, the House of Obrenović. Paul spent his early years in Geneva, where he grew up a lonely and rather neglected child in the household of his uncle, King Peter Karađorđević. Among his relatives, he was affectionately known as “Toto.”

The long and violent feud between the Houses of Karađorđević and Obrenović, which had begun in 1817, came to an end in 1903 when a military coup overthrew and brutally killed King Alexander I of the Obrenović line. In the aftermath, Peter Karađorđević returned to Serbia to ascend the throne as King Peter I. That same year, young Paul accompanied his uncle to Serbia for the first time.

In 1912, he chose to attend the University of Oxford—a rare decision among the Serbian elite, who typically pursued their studies in either Paris or Saint Petersburg.

Paul was educated at Christ Church, Oxford, where he was a member of the exclusive Bullingdon Club – a dining club notorious for its wealthy members, grand banquets and boisterous rituals. Cultivated like his closest friends Prince George, Duke of Kent, and Sir Henry Channon, his outlook on life was said to be British. Paul often said that he "felt like an Englishman". Channon called Paul "the person I have loved most". For a time, Paul and Channon lived together in a house in London together with another of Channon's lovers Lord Gage. A cultured and easy-going bon vivant who inspired much affection from his friends, Paul when not associating with the British aristocracy collected paintings by Monet, Titian and van Gogh.

Despite the fact that it was Austria-Hungary that declared war on Serbia on 28 July 1914, Paul only joined the Royal Serbian Army in November 1914, serving for six months before returning to Britain in May 1915. Paul returned to service with the Royal Serbian Army, which was now in exile in Greece in January-April 1917 before again returning to Britain. His military record during both of his tours of duty was described as "undistinguished" as Paul found he was not cut out to be a soldier. Paul argued that he could be at most service to Serbia by being in London, where he served as a lobbyist for Serbia.

Paul lived in London from 1919 to 1924 and only infrequently visited Belgrade. During his time in London, he was the proverbial "life of the party" who enjoyed socialising with the British elite at parties in London or in various country houses. On October 22, 1923, he married Princess Olga of Greece and Denmark, a sister of Princess Marina, Duchess of Kent. The Duke of York (the future King George VI), was the best man at his wedding in Belgrade. In January 1924, he returned to Yugoslavia. Paul's cousin, King Alexander, seemed to have had in mind installing him in some sort of vice-regal position in Zagreb to govern the Croats; Alexander enjoyed Paul's company, finding him to be a witty conversationalist with a "breadth of vision" and a "cool intellect". However, the king decided that Paul was too sympathetic towards Croat complaints about the unitary state created by the 1921 Vidovdan Constitution, and decided not to give him the vice-regal position, much to Paul's frustration.