The Naval Meritorious Service Medal is an account of the development of the medal which largely replaced the Distinguished Service Medal from 1918 as an award for acts of gallantry not under enemy fire, as well as providing an appropriate award to recognise the many men who provided long and meritorious service. This medal has previously remained largely un-researched but this account draws together the surviving recommendations for these awards, providing an analysis of the campaigns for which the awards were made as well as detailing the Army and Royal Air Force Meritorious Service Medal awards made to Naval personnel. The work provides a definitive history of these awards, and is a fitting companion to the author's previous work detailing the history of the Distinguished Service Medal.