Major Otho Hamilton (c.1690 – 26 February 1770) was a military officer of the 40th Regiment of Foot who served on the Nova Scotia Council and as Governor of Placentia.
He was born in Edinburgh, Scotland, one of the 12 children of Thomas and Grizel Hamilton.
He became involved in the government of Nova Scotia, firstly as secretary and then as a member of the Council.
In 1744 he was appointed Lieutenant-governor of Placentia, Newfoundland, where he worked hard to improve the conditions of the colony and the military garrison, remaining there until at least 1764.
He was the father of Captain John Hamilton who was taken into captivity during the Siege of Grand Pre.