Fredrik Wilhelm von Otter (11 April 1833 – 9 March 1910) was a Swedish friherre, naval officer and politician, most notably serving as Prime Minister of Sweden from 1900 to 1902. Otter was born on the Fimmersta estate (Töreboda Municipality) in Västergötland and belonged to a wealthy and aristocratic family. He entered the Royal Swedish Navy as second lieutenant at the age of 17, but remained without promotion for a long time. Meanwhile he served in the British Royal Navy 1857–1861, participating in campaigns against pirates in the South China Sea, and took part in one of Adolf Erik Nordenskiöld's North Pole expeditions in 1868, as commander of the expedition ship Sofia. He was promoted to commander and made aide-de-camp of Crown Prince Oscar, the Duke of Östergötland, in 1872 and remained