List of ships named Union

• was a Royal Navy sixth rate post ship, built in 1755. She served during the French and Indian War, most notably at Louisbourg and Quebec, and the American Revolution, during which she captured two French privateers. The Royal Navy sold her in 1783. J. Montgomery purchased her and she became the Greenland whaler Union. Then in 1790–91 she became a slaver, making five slave-trading voyages. Between 1796 and 1802 she made two voyages for the British East India Company. She then traded between London and Liverpool. She was last listed in 1804.
• was an 8-gun bomb ketch launched in 1759 for the British Royal Navy that it sold in 1774. New owners renamed her Union. She made two voyages as a Greenland whaler before becoming a London-based transport. She remained a transport until she was lost on 20 May 1782 off the Malabar coast of India.
• was launched in Philadelphia. She sailed between England, North America, and the West Indies. She made one voyage as a slave ship and then returned to her previous trade. A privateer captured her in 1781.
• first appeared in online records in 1799. She made one voyage as a slave ship before she foundered in 1801 on her way home.
• was launched at Calcutta. She sailed to England and then made five voyages for the British East India Company, between 1805 and 1814. She was wrecked in late 1815 or early 1816.
• , sunk in Fiji in 1804
• was an East Indiaman that made eight apparently uneventful voyages for the EIC before her sale for breaking up in 1819.
• was a screw schooner collier launched at Southhampton and fitted with a 30HP auxiliary engine. She served the Union Steam Collier Line formed in 1853 to carry coal from Wales to Southhampton. She was last listed in Lloyd's Register in 1862. In 1900 Union Steam Collier merged with Castle Line to form Union-Castle Line.
• Union, a steamboat originally named, in Oregon, United States, in the 1860s.