Joseph Anton Blatter (also known in French as "Joseph-Antoine Blatter"; 8 March 1745 — 19 March 1807) was a Swiss prelate and the 73rd and last Prince-bishop of the Diocese of Sion, in the Republic of the Seven Tithings, in the modern Canton of Valais, from 1790 to 1799, and after the French invasion and dissolution of the republic, Bishop of Sion until his death in 1807.