George V (George Frederick Ernest Albert; 3 June 1865 – 20 January 1936) was King of the United Kingdom and the British Dominions, and Emperor of India, from 6 May 1910 until his death in 1936.

Born during the reign of his grandmother Victoria, George was the second son of Albert Edward, Prince of Wales, and was third in the line of succession to the British throne behind his father and his elder brother, Prince Albert Victor. From 1877 to 1892, George served in the Royal Navy, until the unexpected death of his elder brother in early 1892 put him directly in line for the throne. George married his brother's fiancée, Princess Victoria Mary of Teck, the following year, and they had six children. Following the death of Queen Victoria in 1901, George's father ascended the throne as Edward VII, and George was created Prince of Wales. He became king-emperor on his father's death in 1910.

George's reign saw the rise of socialism, communism, fascism, Irish republicanism, and the Indian independence movement, all of which radically changed the political landscape of the British Empire, which itself reached its territorial peak by the beginning of the 1920s. The Parliament Act 1911 established the supremacy of the elected British House of Commons over the unelected House of Lords. As a result of the First World War (1914–1918), the empires of his first cousins Nicholas II of Russia and Wilhelm II of Germany fell, while the British Empire expanded to its greatest effective extent. In 1917, George became the first monarch of the House of Windsor, which he renamed from the House of Saxe-Coburg and Gotha as a result of anti-German public sentiment. He appointed the first Labour ministry in 1924, and the 1931 Statute of Westminster recognised the Empire's dominions as separate, independent states within the British Commonwealth of Nations.

George suffered from smoking-related health problems throughout much of his later reign. On his death in January 1936, he was succeeded by his eldest son, Edward VIII. Edward abdicated in December of that year and was succeeded by his younger brother Albert, who took the regnal name George VI.