Umberto Cagni (24 February 1863 in Asti – 22 April 1932 in Genoa) was a polar explorer and an admiral in the Royal Italian Navy. He is best known for his leadership in a probe, by dogsled, northward over the surface of the Arctic Ocean in 1900. While his party failed in their goal of reaching the North Pole, on 25 April 1900 Cagni and his men achieved the northernmost point achieved by exploration up to that time, 86° 34′ N.
Cagni was born in the fast-growing Kingdom of Italy, which had been proclaimed only two years earlier during the Risorgimento. His well-placed father, a Piedmontese general, bestowed kinship ties that led to young Cagni being accepted for training by the Italian navy as a future officer. He was commissioned as an ensign in 1881.
Cagni advanced in the service in terms of both rank and connections. By 1899 he was a captain in the Regia Marina and a close associate of Prince Luigi Amedeo. The prince was an Italian duke, nephew of the king of Italy, and experienced mountaineer. Organizing a group of 20 Italian and Norwegian men led by himself, the royal duke sailed on 12 June 1899 from Christiania for the recently discovered Franz Josef Land, via Archangel'sk. In far northern Russia, Cagni and Luigi Amedeo obtained the sled dogs that would be a key element of the expedition. On 12 July they sailed north from Archangel'sk aboard their exploration vessel, the Stella Polare, their goal the establishment of a winter base in Franz Josef Land that would give them a jumping-off place to attain the North Pole.