Baron Peter von Uslar (Russian: Пётр Карлович Услар, Pjotr Karlovič Uslar) (1 September [O.S. 20 August] 1816 — (20 July [O.S. 9 July] 1875) was a Russian general, engineer and linguist of German descent, known for his research of languages and ethnography of peoples of Caucasus.
Peter von Uslar was born in Kurovo manor in Vyshnevolotsky District, Tver Governorate, Russian Empire. After graduating from the Chief Engineering School, he graduated from the General Staff Academy and did not have formal education in linguistics.
In 1850 he was appointed member of the Caucasus Department of the Russian Geographical Society and ordered to compile the history of Caucasus. This appointment had eventually led to his interest in researching of Caucasian languages and to his tremendous contribution into the recording of numerous Caucasian languages from various linguistic groups, such as Abkhaz, Ubykh, Svan, Chechen, Avar, Lak, Tabasaran, Lezgian, Dargin, etc.