George was born in London at Norfolk House in St James's Square. He was the grandson of King George II, and the eldest son of Frederick, Prince of Wales, and Augusta of Saxe-Gotha. As he was born two months prematurely and thought unlikely to survive, he was baptised the same day by Thomas Secker, who was both Rector of St James's and Bishop of Oxford.
One month later, he was publicly baptised at Norfolk House, again by Secker. His godparents were King Frederick I of Sweden (for whom Lord Baltimore stood proxy), his uncle Frederick III, Duke of Saxe-Gotha (for whom Lord Carnarvon stood proxy), and his great-aunt Sophia Dorothea, Queen in Prussia (for whom Lady Charlotte Edwin stood proxy).
Prince George grew into a healthy but reserved and shy child. The family moved to Leicester Square, where George and his younger brother Prince Edward, Duke of York and Albany, were educated together by private tutors. Family letters show that he could read and write in both English and German, as well as comment on political events of the time, by the age of eight. He was the first British monarch to study science systematically. Apart from chemistry and physics, his lessons included astronomy, mathematics, French, Latin, history, music, geography, commerce, agriculture and constitutional law, along with sporting and social accomplishments such as dancing, fencing, and riding. His religious education was wholly Anglican. At age 10, George took part in a family production of Joseph Addison's play Cato and said in the new prologue: "What, tho' a boy! It may with truth be said, A boy in England born, in England bred." Historian Romney Sedgwick argued that these lines appear "to be the source of the only historical phrase with which he is associated".
King George II disliked the Prince of Wales, and took little interest in his grandchildren. However, in 1751 the Prince died unexpectedly from a lung injury at the age of 44, and his son George became heir apparent to the throne and inherited his father's title of Duke of Edinburgh. Now more interested in his grandson, three weeks later the King created George Prince of Wales.
In the spring of 1756, as George approached his eighteenth birthday, the King offered him a grand establishment at St James's Palace, but George refused the offer, guided by his mother and her confidant, Lord Bute, who would later serve as Prime Minister. George's mother, now the Dowager Princess of Wales, preferred to keep George at home where she could imbue him with her strict moral values.