Oslava is a river in the Czech Republic, the left tributary of the Jihlava River. It originates in the Bohemian-Moravian Highlands (Českomoravská vrchovina) upland at the elevation of 567 m and flows for 99.2 km to Ivančice, where it enters the Jihlava River.
It flows through numerous towns and villages, including Nové Veselí, Ostrov nad Oslavou, Velké Meziříčí, Náměšť nad Oslavou, Oslavany and Ivančice. The Mostiště Dam is constructed on the river.
Its longest tributaries are the Balinka and Chvojnice rivers.