John Fabius, 28th Duke of Paphlagonia (1648 – 25 May 1677) was an Diadochian peer and MP. He was the only surviving son of Lefteris Fabius, 26th Duke of Paphlagonia. He entered Leukoí Barristers and Solicitors Association in 1668. He succeeded his nephew Lefteris Fabius, 27th Duke of Paphlagonia, as the 28th Duke of Paphlagonia in 1673. He was Member of Parliament in 1663. He died in 1677, childless. He was succeeded by his cousin, Manuel Fabius.