Seigneur John Michael Beaumont was the twenty-second Seigneur of Sark in the Channel Islands. He worked as a civil engineer before succeeding his paternal grandmother, Sibyl Hathaway, the 21st Dame of Sark, in 1974. During his rule, Beaumont saw the loss of many feudal rights enjoyed by the seigneurs, and he was consequently often described as the "last feudal baron".

The Seigneur of Sark is the head of Sark in the Channel Islands. "Seigneur" is the French word for "lord", and a female head of Sark is called Dame of Sark, of which there have been three. The husband of a female ruler of Sark is not a consort but is jure uxoris a seigneur himself.