Marshal of the Royal Air Force Hugh Montague Trenchard, 1st Viscount Trenchard, GCB, OM, GCVO, DSO (3 February 1873 – 10 February 1956) was a British military officer who was instrumental in establishing the Royal Air Force. He has been described as the "Father of the Royal Air Force".

During his formative years, Trenchard struggled academically, failing many examinations and only just succeeding in meeting the minimum standard for commissioned service in the British Army. As a young infantry officer, he served in India; with the outbreak of the Boer War, he volunteered for service in South Africa. While fighting the Boers, he was critically wounded; as a result of his injury, he lost a lung, was partially paralysed and returned to Great Britain. On medical advice, Trenchard travelled to Switzerland to recuperate, but owing to the boredom he suffered, took up bobsleighing. After a heavy crash, he found that his paralysis was gone and that he could walk unaided. Following further recuperation, he returned to active service in South Africa.

After the end of the Boer War, Trenchard saw service in Nigeria, where he was involved in efforts to bring the interior under settled British rule and quell intertribal violence. During his time in West Africa, he commanded the Southern Nigeria Regiment for several years.

Trenchard learned to fly in summer 1912, and gained his aviator's certificate (No. 270) on 31 July, flying a Henry Farman biplane of the Sopwith School of Flying at Brooklands. He was subsequently appointed as second-in-command of the Central Flying School. He held several senior positions in the Royal Flying Corps during the First World War, serving as the commander of the Royal Flying Corps in France from 1915 to 1917. In 1918, he briefly served as the first Chief of the Air Staff before taking up command of the Independent Air Force in France. Returning as Chief of the Air Staff under Winston Churchill in 1919, Trenchard spent the following decade securing the future of the Royal Air Force. He was Metropolitan Police Commissioner in the 1930s and a defender of the RAF in his later years. He is recognised today as one of the early advocates of strategic bombing.

Hugh Montague Trenchard was born at 6 Haines Hill in Taunton, England, on 3 February 1873. He was the third child and second son of Henry Montague Trenchard and his wife Georgiana Louisa Catherine Tower Skene. Trenchard's father was a former captain in the King's Own Yorkshire Light Infantry who was working as an articled clerk in a legal practice and his mother was the daughter of the Royal Navy captain John McDowall Skene. Although in the 1870s the Trenchards were living in an unremarkable fashion, their forebears had played significant roles in English history. Notable ancestors were Sir Thomas Trenchard, a High Sheriff of Dorset in the 16th century and Sir John Trenchard, the Secretary of State under William III.

When Hugh Trenchard was two, the family moved to Courtlands, a manor house in Norton Fitzwarren, less than three miles (4 km) from the centre of Taunton. The country setting meant that he could enjoy an outdoor life, including spending time hunting rabbits and other small animals with the rifle he was given on his eighth birthday. It was during his junior years that he and his siblings were educated at home by a resident tutor, whom Trenchard did not respect. Unfortunately for his education, the tutor was neither strict enough nor skilful enough to overcome the children's mischievous attempts to avoid receiving instruction. As a consequence, Trenchard did not excel academically; however, his enthusiasm for games and riding was evident.

At the age of 10, he was sent to board at Allens Preparatory School near Botley in Hampshire. Although he did well at arithmetic, he struggled with the rest of the curriculum. However, his parents were not greatly concerned by his educational difficulties, believing that it would be no impediment to him following a military career. Georgina Trenchard wanted her son to follow her father's profession and enter the Royal Navy. In 1884 he was moved to Dover where he attended Hammond's, a cramming school for prospective entrants to HMS Britannia. He failed the Navy's entrance papers, and at the age of 13 he was sent to the Reverend Albert Pritchard's crammer, Hill Lands in Wargrave, Berkshire. Hill Lands prepared its pupils for Army commissions and, as before, Trenchard did not apply himself to his studies, preferring sports (rugby in particular) and practical joking.

In 1889, when he was 16 years old, his father, who had become a solicitor, was declared bankrupt. After initially being removed from Hill Lands, the young Trenchard was only able to return thanks to the charity of his relatives. He subsequently failed the Woolwich examinations twice and was then relegated to applying for the Militia which had lower entry standards. Even the Militia's examinations proved difficult for Trenchard, and he failed in 1891 and 1892. During this period he underwent a period of training as a probationary subaltern with the Forfar and Kincardine Artillery. Following his return to Pritchard's, he achieved a bare pass in March 1893. At the age of 20, he was gazetted as a second-lieutenant in the Second Battalion of the Royal Scots Fusiliers and posted to India.