Çenebaz Osman Efendi (Osman Efendi the Chatterer or the Loudmouthed), formally named as Yenişehirli Osman Efendi (either from Yenişehir near Bursa, or from Giannitsa, now in Greece, which was also called "Yenişehr-i Fener" in Ottoman times) in Ottoman sources, was an Ottoman diplomat who was the first plenipotentiary in the first peace conference, held in Focşani, today in Romania, starting August 19, 1772, among the several that were organised during the ten-month truce (May 10, 1772 – March 21, 1773) in the course of the Russo-Turkish War (1768–1774). His Russian counterparts were Grigory Grigoryevich Orlov, Catherine II's lover and counsellor, and Aleksey Mikhailovich Obreskov (1720–1787), Russia's peacetime ambassador in İstanbul.