The Allied occupation of İstanbul after World War I had a transformative impact on the city’s musical entertainment sector. The arrival of large numbers of military personnel created additional demand for music halls, cabarets, cafe-chantants, and concert venues. Servicemen’s musical preferences were catered for by resident İstanbulites and others who found refuge in the city, creating opportunities for musicians and entertainment entrepreneurs to benefit from new and existing patrons. This buoyant market was further harnessed for charitable causes directed at new categories of people in need. The distinct political climate introduced with occupation also made its mark on musical performance, with nationalist and socialist groups using concerts to promote messages of salvation. The end of the occupation led to the dispersal of these musicians to new locations, such as the new Republican capital of Ankara, which attracted talents intent on staying in Turkey, and Athens and Thessaloniki, which received Greek Orthodox musicians fleeing the new Turkish nationalist regime, and still further afield. Using British, French, and Ottoman government documents, memoirs, and newspapers, the article investigates this process of musical convergence and divergence and analyses the local and global impact of the aural encounters of this overlooked period in İstanbul’s cultural history.