Iwami Province (石見国 Iwami-no kuni?) was an old province of Japan in the area that is today the western part of Shimane Prefecture. It was sometimes called Sekishū (石州?). Iwami bordered Aki, Bingo, Izumo, Nagato, and Suō provinces.
In the Heian era (794-1192) the capital was at modern-day Hamada. In the Kamakura era (1192-1333) the Masuda clan belonged to the Minamoto clan (Genji) and conquered Iwami Province.
During the Muromachi era and Sengoku Period, the battles were very furious in this area. At first, the Masuda clan was in alliance with the Ouchi clan in neighboring Sufu, but later the Masuda clan belonged to the Mouri clan in neighboring Aki.