Bishopric of Ösel-Wiek (in Estonian Saare-Lääne) was a semi-independent principality in what is now Saare and Lääne counties of Estonia. The bishopric was created in 1228 by Papal legate William of Modena as compromise between the church and the Livonian Order, main power of the region. It was part of Livonian Confederation. The seat of the bishop was Hapsal (in Estonian Haapsalu) . Another important possession was the castle of Ahrensburg (Kuressaare) in the island of Ösel. The principality ceased to exist in 1560 when its last prince-bishop Johannes von Monnickhusen sold it to Denmark.

The Bishops of Ösel-Wiek

• Heinrich I 1234-1260
• Konrad I 1297-
• Jacobus 1323-1337
• Winnrich von Kniprode 1383-1419
• Kaspar Schuwenpflug 1420-1423
• Christian Kuband 1423-1431
• Johannes Schutte 1431-1439
• Ludolph Grove 1439-1456
• Johannes II Croweli 1439-1457
• Jodocus Hoensteini 1458-1471
• Johannes III Orgas 1491-1515
• Johannes IV Kievel 1515-1527
• Reinhold Buxhöveden (1532)
• Johannes von Monnickhusen 1541-1560