The Royal Naval Reserve (RNR) is the volunteer reserve force of the Royal Navy in the United Kingdom.

The present Royal Naval Reserve was formed in 1958, merging the former Royal Naval Reserve, founded in 1859 as a reserve of professional seamen, and the Royal Naval Volunteer Reserve (RNVR), a reserve of volunteers founded in 1903. The RNR is often called the "Wavy Navy" after the wavy sleeve stripes of officers in the RNVR and RNR during World War II.

The modern RNR has fourteen Royal Naval Reserve Units. These are

• HMS Scotia (Rosyth)
• HMS Cambria (Sully)
• HMS Dalriada (Greenock)
• HMS Flying Fox (Bristol)
• HMS Calliope (Gateshead)
• HMS President (London)
• HMS Eaglet (Liverpool)
• HMS Vivid (Devonport)
• HMS Sherwood (Nottingham)
• HMS King Alfred (Portsmouth)
• HMS Forward (Birmingham)
• HMS Caroline (Belfast)
• HMS Wildfire (Northwood)
• HMS Ferret (Chicksands)

There are also naval reserve forces operated by other Commonwealth navies, e.g. the Royal Australian Naval Reserve (RANR), the Royal New Zealand Naval Volunteer Reserve (RNZNVR), etc. Previously there were also colonial RNVR units, e.g. the Straits Settlements Royal Naval Volunteer Reserve (SSRNVR).