Ernst Otto von Diederichs was a German admiral of the Prussian Navy who served both the Kingdom of Prussia and the German Empire. He was the first governor of the German Jiaozhou Bay concession in China.

The Kiautschou Bay Leased Territory was a German leased territory in Imperial and Early Republican China from 1898 to 1914. Covering an area of 552 km2 (213 sq mi), it centered on Kiautschou Bay on the southern coast of the Shandong Peninsula. The administrative center was at Tsingtau (Qingdao). It was operated by the East Asia Squadron of the Imperial German Navy. The Russian Empire resented the German move as an infringement on Russian ambitions in the region.