Robert Preston, 1st Baron Gormanston was an Anglo-Irish nobleman, statesman and judge of the fourteenth century. He held several senior judicial offices including, for a brief period, that of Lord Chancellor of Ireland. He was the founder of the leading Anglo-Irish Preston family whose titles included Viscount Gormanston and Viscount Tara.

Viscount Gormanston is a title in the Peerage of Ireland created in 1478 and held by the head of the Preston family, which hailed from Lancashire. It is the oldest vicomital title in the British Isles; the holder is Premier Viscount of Ireland.