Eight ships of the Royal Navy have borne the name HMS Union:
was a fifth rate of unknown origin, possibly a hired vessel. She was burnt in 1693 to avoid being captured by the French. HMS Union was a 90-gun second rate, previously named . She was renamed HMS Union in 1709, was rebuilt in 1726 and broken up in 1749. was a 90-gun second rate launched in 1756. She was converted into a hospital ship in 1799 and was renamed HMS Sussex in 1802. She was broken up in 1816. was a 3-gun gunvessel purchased in 1794 and listed until 1798. was a cutter in service in 1806 and broken up in 1810. was a 98-gun second rate launched in 1811 and broken up in 1833. was the mercantile City of Kingston that the Navy purchased in 1823 for service as a 3-gun schooner; she was wrecked in 1828. was a U-class submarine launched in 1940 and sunk in 1941.