Otis, James (1725–1783), an American orator and statesman. Otis was one of the most influential figures in the pre-Revolutionary period. Although a leader of the New England radicals, he had conservative impulses that from time to time restrained his revolutionary ardor. He tried to prevent violence and sought legal and philosophical means of resolving the colonies' differences with Britain.

Otis's theory of the constitutional relationship between the colonies and the mother country became an important principle in the American Revolution. In 1761, when arguing against the writs of assistance, Otis stated that the authority of Parliament was restricted by British common law (law established by custom) and by natural law (rights that individuals derive from nature). He is sometimes credited with originating the slogan, "Taxation without representation is tyranny," but his actual words on this subject were much less dramatic.

Otis was one of the most effective pamphleteers in the colonies. His writings included A Vindication of the Conduct of the House of Representatives (1762) and Rights of the British Colonies Asserted and Proved (1764). The second developed his views on the natural rights of Englishmen, denying Parliament's authority to tax the colonies.

Otis was born in West Barnstable, Massachusetts, and graduated from Harvard College. He practiced law in Boston before his appointment as king's advocate general in 1756. Otis resigned in 1761 to act as counsel for a group of merchants opposing the writs of assistance. Although he lost the case, his forceful conduct of it led to his election to the Massachusetts legislature, where he served from 1761 to 1771.

In 1764 Otis became chairman of a committee of the legislature that was to correspond with other colonial assemblies. In 1765 he helped to arrange the Stamp Act Congress. With Samuel Adams, he led the majority in the legislature in opposition to Parliament's revenue acts, 1766–69.

In 1769 Otis suffered a blow on the head during a quarrel with a British official. This injury hastened a mental deterioration that had become increasingly noticeable over a period of years, and forced his retirement from public life in 1771.