The Short S.45 — also known as the Short T.5 after its naval serial number — was a training biplane built for Britain's Royal Navy by Short Brothers in 1912. It was the forerunner of another three identical aircraft (designated S.48, S.49, and S.50 by Shorts) delivered to the Royal Navy and Royal Flying Corps during 1912 and 1913. The Royal Naval Air Service was still operating the type when World War I broke out in 1914.