奥卡河（俄语：Ока）是俄罗斯伏尔加河最大的支流，全长1,500公里。语出芬兰-乌戈尔诸语，可能是梅晓拉语，意思是「河流」。

俄罗斯首都莫斯科就位于奥卡河的支流莫斯科河畔。另一座大城市下新城位于河口。其他沿岸主要城市有：奥廖尔、卡卢加、科洛姆纳、梁赞、捷尔任斯克。

Oka (Russian:Ока́, IPA: [ɐˈka]) is a river in central Russia, the largest right tributary of the Volga. It flows through the regions of Oryol, Tula, Kaluga, Moscow, Ryazan, Vladimir, and Nizhny Novgorod and is navigable over a large part of its total length, as far upstream as to the town of Kaluga. Its length exceeds 1,500 kilometres (930 mi). The Russian capital Moscow sits on one of the Oka's tributaries—the Moskva River.