HMS Cayman (K506) was a Colony-class frigate of the United Kingdom that served during World War II.

She originally was ordered by the United States Navy as the Tacoma-class patrol frigate USS Harland (PF-78) and was transferred to the Royal Navy prior to completion.

The ship, originally designated a "patrol gunboat," PG-186, was ordered by the United States Maritime Commission under a United States Navy contract as USS Harland.

She was reclassified as a "patrol frigate," PF-78, on 15 April 1943 and laid down by the Walsh-Kaiser Company at Providence, Rhode Island, on 15 July 1943.

Transferred to the United Kingdom under Lend-Lease on 20 January 1944, the ship served in the Royal Navy as HMS Cayman (K506) on patrol and escort duty.