The Militia was reconstituted in 1921 as one infantry battalion, the Royal Militia of the Island of Jersey.
In World War II, the Island was demilitarised, 11 officers and 193 men of the militia left on the SS Hoder to England, where they formed the nucleus of the 11th (Royal Militia Island of Jersey) Battalion, The Hampshire Regiment. It was a training battalion, based in the United Kingdom throughout the war until it was disbanded in 1946. Because the National Service Act did not apply in the Channel Islands, the Royal Militia of the Island of Jersey went into suspended animation (sc. it existed on paper, but had no personnel) until it was formally disbanded, along with the other British Militia regiments, in 1953